You see, that is the problem with volunteer spuds. Unless you have a very good record of exactly what you planted where last year, which I don't, then you can't always be sure what the spuds are you are unearthing....unless they happen to be pink fur apples! Unmistakeable. Had PFA chips with our home made Cornish pasties for supper tonight! :P
(http://i15.photobucket.com/albums/a364/Mrsava/pink_fur_apple_volunteers.jpg)