Cheers guys. Thanks for the tip Neil, but I've already got it sorted. I just bought some 20mm-wide velcro strapping (hooks one side, loops the other), cut it to length and used that. It's a bit less elegant than proper battery straps, but should do the job perfectly well.
In other news, the ESC plate is basically done, and the MMM is all calibrated to my radio. BEC is also solid so far...not that it shouldn't be with the new firmware, but I have a knack of getting duff items lol. Kicking out an exact 5.50V.
The only thing that is puzzling me slightly is the fan. I know that with the V1 it'll stay on permanently (a good thing IMO), but I've noticed it takes time to build up speed each time I turn the ESC on. I'd usually think it was just the fan motor bedding in, but they're usually brushless themselves. It's no problem obviously, I'm just wondering if it's normal. Anyone else experienced this?