Have you quoted the right price/size there, Rob?
Just wondering as that would make the 334AH battery around £710 and you could get the superior (with integral heater) 320AH Polarmax from Alpha Batteries for £500 without any discount.
Instead of the 668AH Drift at around £1,050, you could get Alpha's Polarmax 640AH for £900 (without any discount).
Yes, the sizes are a little smaller, but the heater makes up for that as well as the lower price.