My first seed potatoes

[Sanjo]

are long white shoots bad? I just got some from b and q and I got the ones with about inch longh shoots, I just thought that was what would happen when they chit I'll take them back if they are wrong

Long and white is because they have chitted in the dark. You could rub them off and leave them in an egg box to start again.
Other viners may have other views though.