Are you sure!?!, I've not heard of this before. Every time I've approached in the past I've been shrugged off saying the limits are the limits, unless I go in for a buisness line (which I never will).
I'll give them a ring this evening when I've finished work... if I get a positive answer then I'll owe you a few pints!
Yeah I'm pretty sure, it was a while back that I last heard it being done but I don't see why they would stop. They would just lose customers if they didn't offer it.