Max-Amps have offered me at least 15% off a new pack, which is pretty damn decent of them especially as I am not the original purchaser of the cells. The guy I spoke to on live help said he will talk to his boss on Monday and let me know if he can do any better.
I've already looked at Flightpower, buy I'll need to get the ruler out and see what size I need.
I've made up a Y-lead for tomorrow and will be running twin 7.4v Core packs, charging is going to be a problem, so if anyone has a spare lipo charger I can borrow...