Saving seed potatoes for same year planting

A work mate and i decided to have a go at growing some spuds for Christmas, i bought certified charlotte seed potatoes and he decided to have a go with some from his early crop. Mine are now filling the pots but his are showing no signs of shooting at all. Is there a specific way of treating them in order to stimulate them into growth during the same year?

Totty

Ok thanks DD, do they have to be kept anywhere in particular, fridge, dark shed etc?

Ok, so try 2 months in the fridge, then bring out somewhere bright and warm and hope for the best! Thanks

Totty