Most stores seem to have withdrawn canned pie fillings (presumably because people either want to do things the easy way, and buy ready made pies, or to make their pies from the basic ingredients). However a bit of Googling has found a few (fairly recent) posts suggesting that Asda still have them (including apricot).
Otherwise, there's a fairly simple recipe for making your own apricot pie filling (using dried apricots) about a quarter of the way down this page:
http://shirleygoode.b...06/icing-on-cake.html
Chris