Need to replace the bearings on my rear hub, and a set of the five you need are £24 on CRC. Looking on eBay you can get the set for £12. Are these cheaper ones likely not to be legit Hope bearings? And if not, does it really matter… would there be any real difference?

Decent branded (INA/FAG/SKF/etc) bearings cost around £8 each from my local bearing supplier, the hope kits use INA bearings so are a bargain. Cheap Chinese bearings are not a cost saving, as you’ll end up replacing them (sometime a lot) sooner IME. If you can find a cheaper kit that uses branded bearings go for it.

Cool thanks, I’ll have a scout and go for cheapest official Hope ones I can find.

Any decent brand will do, you don’t need a hope kit, these are the bearings your looking for:
61903 x2 for Hub
61802 x2 for freehub
61902 x1 for freehub

They need to be all 2RS (for rubber shielded on both sides) eg. “61902 2RS”