I guess this is because they have a 1 instead of a 2 on the box but is there anyway to play them in a UK DVD player?
you can play them if you get your player made into a multi region player you can do this yourself in a few ways, look your make and model up on the net and you may find it listed to do this
region 1 signifies that it for the US anongst other countries market and region 2 is for the european market
if you cant find any codes, post the make and model on here and we can look it up for you. good luck :D