Play.com seem to have added some new titles to their 3 for 2 Blu Ray offers, some of which are the original batman movies:
Batman: The Movie (£17.99)
Batman (Tim Burton) (£13.99)
Batman Returns (£13.99)
Batman Forever (£13.99)
Batman & Robin (£13.99)
Okay so the last 2 aren't really worth bothering with, but good for a collection, plus you can also add the animated Batman: Gotham knight to that and make it 6 for 4 if you're feeling frivolous!!
If you get 3 of the 4 'latest' versions you're looking at £27.98, not forgetting your 4% Quidco bring it down to £26.86 which makes it about £8.95 each! I think the next cheapest is Amazon for £12.98 each