Well, I got the RMA replacement from Overclockers.co.uk - it is a v2 card. Interestingly, the box says GPU 620Mhz / mem 1485Mhz on the side, but there is a sticker on the front that says GPU 587Mhz / mem 1540Mhz. The old card was a v1.
I think it is working fine now. I was occasionally getting green speckles on the screen, sometimes in 2D mode (eg: when watching movies). This was like a few hundred single green pixels dotted randomly across the screen, and moving about. They'd come and go - mostly weren't there. I completely removed all the ATI drivers, Control Centre and Hydravision, ran DriverCleaner over it in safe mode, and reinstalled. So far has been OK after re-install, but have yet to really test it thoroughly.