Thanks Mal and Galina.
Mal - have you weighed yours - it looks twice as big as mine! I think I will pick mine and keep it in the greenhouse till the competition, it shouldn't lose much weight should it?
Galina - I don't know the variety, someone on here kindly sent me the seed.
I still can't believe how big it is. Considering that from the day I planted it out I have never fed or watered it, it's done really well.