Grape vines 2 quid a pop

I'm not sure how many members can get into central london easily or not, but here goes.There's a bloke on Leather Lane market selling grape vines at £2 a go.I wasnt sure if they were any good or not but i took a chance &bought a acouple to show around the allotment& get some opinions.Well i've been asked to get another12 plants next chance i get.