Yellow tomato ID please?

Earlier this year I bought 24 heritage tomato plants from a specialist nursery in Downham Market for a fiver They had no labels, so we don't know the varieties.

This one is pure gold! Soft and sweet, full of flavour but not too acid. I'd like to grow them next year but in case we're too greedy to save any seed

Could anyone tell me the variety please? It's slightly paler than in the photo, pale lemon yellow rather than orange/gold yellow.

 

Yellow Plum..Gold Nugget maybe??

 

cream saussage?

 

Thank you - it's difficult to be certain isn't it? The concensus seems to be either cream sausage, cream banana (are they the same thing?) or golden banana! I think I'll have to restrain myself and save seed