diff --git a/inc/LauBlattWeisskopfFactor.hh b/inc/LauBlattWeisskopfFactor.hh
--- a/inc/LauBlattWeisskopfFactor.hh
+++ b/inc/LauBlattWeisskopfFactor.hh
@@ -36,12 +36,13 @@
 #define LAU_BLATTWEISSKOPFFACTOR
 
 #include "Rtypes.h"
+#include "TString.h"
 
 class LauParameter;
 class LauResonanceInfo;
 
 
-class LauBlattWeisskopfFactor {
+class LauBlattWeisskopfFactor final {
 
 	public:
 		//! Define the allowed types of barrier factors 
@@ -83,8 +84,8 @@
 		//! Constructor
 		LauBlattWeisskopfFactor( const LauResonanceInfo& resInfo, const Double_t resRadius, const BarrierType barrierType, const RestFrame restFrame, const BlattWeisskopfCategory category );
 
-		//! Destructor
-		virtual ~LauBlattWeisskopfFactor();
+		//! Constructor
+		LauBlattWeisskopfFactor( const Int_t spin, const Double_t resRadius, const BarrierType barrierType, const RestFrame restFrame, const BlattWeisskopfCategory category );
 
 		//! Method to create a new factor with cloned radius parameter
 		/*!
@@ -110,10 +111,6 @@
 		*/
 		Double_t calcFormFactor( const Double_t p ) const;
 
-	protected:
-		//! Set the name of the radius parameter
-		TString setRadiusName( const LauResonanceInfo& resInfo, const BlattWeisskopfCategory category );
-
 	private:
 		//! Copy constructor
 		LauBlattWeisskopfFactor( const LauBlattWeisskopfFactor& other, const UInt_t newSpin, const BarrierType newBarrierType );
@@ -121,6 +118,15 @@
 		//! Copy assignment operator (not implemented)
 		LauBlattWeisskopfFactor& operator=( const LauBlattWeisskopfFactor& other );
 
+		//! Set the name of the radius parameter
+		TString setRadiusName( const LauResonanceInfo& resInfo, const BlattWeisskopfCategory category );
+
+		//! Set the name of the radius parameter
+		TString setRadiusName( const BlattWeisskopfCategory category );
+
+		//! Set the name of the radius parameter
+		TString setRadiusName( const TString& categoryName );
+
 		//! Resonance spin
 		const UInt_t spin_;
 
diff --git a/src/LauBlattWeisskopfFactor.cc b/src/LauBlattWeisskopfFactor.cc
--- a/src/LauBlattWeisskopfFactor.cc
+++ b/src/LauBlattWeisskopfFactor.cc
@@ -58,8 +58,14 @@
 	std::cout << "INFO in LauBlattWeisskopfFactor constructor : creating radius parameter for category \"" << categoryName << "\", with initial value " << resRadius << std::endl;
 }
 
-LauBlattWeisskopfFactor::~LauBlattWeisskopfFactor()
+LauBlattWeisskopfFactor::LauBlattWeisskopfFactor( const Int_t spin, const Double_t resRadius, const BarrierType barrierType, const RestFrame restFrame, const BlattWeisskopfCategory category ) :
+	spin_(spin),
+	radius_(new LauParameter("NEED_A_GOOD_NAME",resRadius,0.0,10.0,kTRUE)),
+	barrierType_(barrierType),
+	restFrame_(restFrame)
 {
+	TString categoryName = this->setRadiusName( category );
+	std::cout << "INFO in LauBlattWeisskopfFactor constructor : creating radius parameter for category \"" << categoryName << "\", with initial value " << resRadius << std::endl;
 }
 
 LauBlattWeisskopfFactor::LauBlattWeisskopfFactor( const LauBlattWeisskopfFactor& other, const UInt_t newSpin, const BarrierType newBarrierType ) :
@@ -72,61 +78,61 @@
 
 TString LauBlattWeisskopfFactor::setRadiusName( const LauResonanceInfo& resInfo, const BlattWeisskopfCategory category )
 {
-	TString name = "BarrierRadius_";
-	TString categoryName;
+	switch (category) {
+		case Indep :
+			return this->setRadiusName( resInfo.getSanitisedName() );
+		default :
+			return this->setRadiusName( category );
+	}
+}
 
+TString LauBlattWeisskopfFactor::setRadiusName( const BlattWeisskopfCategory category )
+{
 	switch (category) {
-		case Parent :
-			categoryName = "Parent";
-			break;
+		case Default :
+			return this->setRadiusName("Unknown");
 		case Indep :
-			categoryName = resInfo.getSanitisedName();
-			break;
+			// We shouldn't ever end up here
+			return this->setRadiusName("Unknown");
+		case Parent :
+			return this->setRadiusName("Parent");
 		case Light :
-			categoryName = "Light";
-			break;
+			return this->setRadiusName("Light");
 		case Kstar :
-			categoryName = "Kstar";
-			break;
+			return this->setRadiusName("Kstar");
 		case Charm :
-			categoryName = "Charm";
-			break;
+			return this->setRadiusName("Charm");
 		case StrangeCharm :
-			categoryName = "StrangeCharm";
-			break;
+			return this->setRadiusName("StrangeCharm");
 		case Charmonium :
-			categoryName = "Charmonium";
-			break;
+			return this->setRadiusName("Charmonium");
 		case Beauty :
-			categoryName = "Beauty";
-			break;
+			return this->setRadiusName("Beauty");
 		case StrangeBeauty :
-			categoryName = "StrangeBeauty";
-			break;
+			return this->setRadiusName("StrangeBeauty");
 		case CharmBeauty :
-			categoryName = "CharmBeauty";
-			break;
+			return this->setRadiusName("CharmBeauty");
 		case Custom1 :
-			categoryName = "Custom1";
-			break;
+			return this->setRadiusName("Custom1");
 		case Custom2 :
-			categoryName = "Custom2";
-			break;
+			return this->setRadiusName("Custom2");
 		case Custom3 :
-			categoryName = "Custom3";
-			break;
+			return this->setRadiusName("Custom3");
 		case Custom4 :
-			categoryName = "Custom4";
-			break;
-		default :
-			categoryName = "Unknown";
-			break;
+			return this->setRadiusName("Custom4");
 	}
+	// We should never get here but gcc seems to think we can
+	return this->setRadiusName("Unknown");
+}
+
+TString LauBlattWeisskopfFactor::setRadiusName( const TString& categoryName )
+{
+    TString name = "BarrierRadius_";
+    name.Append(categoryName);
 
-	name.Append(categoryName);
-	radius_->name(name);
+    radius_->name(name);
 
-	return categoryName;
+    return categoryName;
 }
 
 LauBlattWeisskopfFactor* LauBlattWeisskopfFactor::createClone( const UInt_t newSpin, const BarrierType newBarrierType )
diff --git a/src/LauResonanceMaker.cc b/src/LauResonanceMaker.cc
--- a/src/LauResonanceMaker.cc
+++ b/src/LauResonanceMaker.cc
@@ -632,13 +632,35 @@
 	// Look up the category in the category information map
 	BWFactorCategoryMap::iterator factor_iter = bwFactors_.find( LauBlattWeisskopfFactor::Parent );
 
-	if ( factor_iter != bwFactors_.end() ) {
+	if ( factor_iter == bwFactors_.end() ) {
+		// If the category is currently undefined we need to create it
+		bwFactor = new LauBlattWeisskopfFactor( resSpin, 4.0, bwBarrierType_, bwRestFrame_, LauBlattWeisskopfFactor::Parent );
+		std::cerr<<"WARNING in LauResonanceMaker::getParentBWFactor : Default radius 4.0 set for Blatt-Weisskopf factor category: Parent"<<std::endl;
+
+		BlattWeisskopfCategoryInfo& categoryInfo = bwFactors_[LauBlattWeisskopfFactor::Parent];
+		categoryInfo.bwFactor_ = bwFactor;
+		categoryInfo.defaultRadius_ = bwFactor->getRadiusParameter()->value();
+		categoryInfo.radiusFixed_ = kTRUE;
+	} else {
 		// If it exists, we can check if the factor object has been created
 		BlattWeisskopfCategoryInfo& categoryInfo = factor_iter->second;
 
 		if ( categoryInfo.bwFactor_ != 0 ) {
 			// If so, simply clone it
 			bwFactor = categoryInfo.bwFactor_->createClone( resSpin, barrierType );
+		} else {
+			// Otherwise we need to create it, using the default value if it has been set
+			if ( categoryInfo.defaultRadius_ >= 0.0 ) {
+				bwFactor = new LauBlattWeisskopfFactor( resSpin, categoryInfo.defaultRadius_, bwBarrierType_, bwRestFrame_, LauBlattWeisskopfFactor::Parent );
+			} else {
+				bwFactor = new LauBlattWeisskopfFactor( resSpin, 4.0, bwBarrierType_, bwRestFrame_, LauBlattWeisskopfFactor::Parent );
+				std::cerr<<"WARNING in LauResonanceMaker::getParentBWFactor : Default radius 4.0 set for Blatt-Weisskopf factor category: Parent"<<std::endl;
+			}
+			categoryInfo.bwFactor_ = bwFactor;
+
+			// Set whether the radius should be fixed/floated
+			LauParameter* radius = bwFactor->getRadiusParameter();
+			radius->fixed( categoryInfo.radiusFixed_ );			
 		}
 	}