Allotments 4 All

My dwarf french beans are the same size (6 inches) they were when I planted them 6 weeks ago despite great feeding and watering. Any ideas why?

At risk of stating the obvious, how tall is this variety supposed to get? Are they flowering yet? You say you have fed them, I don't usually give mine anything until they are cropping to keep them going: perhaps you have been too kind to them?