Edgecote Purple spuds

Has anyone grown these before? Went to Beetham Nurseries in Cumbria which has loads of different varieties of loose spuds and these looked a good choice as they are supposed to be fairly blight resistant and a good all rounder. Bought some Charlottes also re- recommendations from people on this forum. 

My neighbour grew some last yr and gave me a few to try. They went from undercooked to mush in the pan very quickly and did not taste very good. They looked very impressive though before they were cooked. Maybe they need to be steamed instead of boiled.