So, is there a right and a wrong eBay seller to buy these lights from?
As far as I can see they’re all much the same. The general consensus is that the lights are all fine, regardless of source. The batteries are of variable quality, and the chargers aren’t to be trusted. I think you could extend this to any of light designs at this sort of price.
The best option if you really want one is to get the light unit on it’s own and source the battery and charger from reputable UK sellers, as per fudge’s post above.
In hindsight, looking at the time and money I’ve spent messing about with these lights and batteries, I wish I’d just bought one of the Fluxient packs here