diff --git a/Grid/serialisation/BaseIO.h b/Grid/serialisation/BaseIO.h
index 535ab035..531d0e41 100644
--- a/Grid/serialisation/BaseIO.h
+++ b/Grid/serialisation/BaseIO.h
@@ -120,11 +120,16 @@ namespace Grid {
       static constexpr std::size_t Dimension(unsigned int dim) {
         return ( dim == 0 ) ? N : Traits<T>::Dimension(dim - 1); }
       static constexpr std::size_t DimensionNT(unsigned int dim) {
+        std::size_t DimSize = N;
+        bool bGotDimSize = false;
         if( N != 1 ) {
-          if( dim == 0 ) return N;
+          if( dim == 0 )
+            bGotDimSize = true;
           dim--;
         }
-        return Traits<T>::DimensionNT(dim);
+        if( !bGotDimSize )
+          DimSize = Traits<T>::DimensionNT(dim);
+        return DimSize;
       }
     };
     template <typename T, int N> struct Traits<iMatrix<T, N>> {
@@ -138,11 +143,16 @@ namespace Grid {
       static constexpr std::size_t Dimension(unsigned int dim) {
         return ( dim == 0 || dim == 1 ) ? N : Traits<T>::Dimension(dim - 2); }
       static constexpr std::size_t DimensionNT(unsigned int dim) {
+        std::size_t DimSize = N;
+        bool bGotDimSize = false;
         if( N != 1 ) {
-          if( dim == 0 || dim == 1 ) return N;
+          if( dim == 0 || dim == 1 )
+            bGotDimSize = true;
           dim -= 2;
         }
-        return Traits<T>::DimensionNT(dim);
+        if( !bGotDimSize )
+          DimSize = Traits<T>::DimensionNT(dim);
+        return DimSize;
       }
     };
     template <typename T, int N> struct Traits<std::array<T, N>> : Traits<iVector<T, N>> {};