Possibly Begonia 'Leprechaun' ... Google images of it to confirm.

it is definitely a Begonia but I don't know which variety it is.

Hi, I agree, definitely Begonia, and I would say you have a choice, it's either B, bowerae 'leprechaun' as shirley tulip says, or B, 'Norah Bedson, both very similar, google both and see which 1 looks nearest to what you have, Derek.

Thanks everyone