
Wrong link
Your link points to the US version of the app, which is (understandably) not available in the UK app store.
This is the one you need:
http://itunes.apple.com/gb/app/toiletfinder-uk/id338250817?mt=8
3 publicly visible posts • joined 5 Mar 2010
Like Steve Anderson, I've checked my previous Argos email receipts and found one from April 2009 which suffers from this problem. Perhaps not coincidentally, the affected card was used fraudulently around that time and has since been cancelled.
I checked another receipt from July 2009 and that seems to be OK, so it looks like Argos fixed the issue, but didn't do the right thing and announce the problem...
Anyway, I've blogged about my findings here if anyone wants to read more: http://chris.gg/p637