First, welcome to GH.
Second, ergonomic keyboards aren't backlit. Actually, backlighting is often considered anti-ergonomic. You shouldn't be looking at your keyboard, and backlighting puts additional strain on ones eyes, especially when it's blue.
Third, so-called gaming keyboards are a gimmicky BS. All you need for gaming is reliability/durability, at least 4KRO and possibly some extra comfort. Unfortunately, most ergonomic keyboards are only 2KRO. Make sure to buy PBT/POM keycaps (they last longer and don't get sticky when your hands sweat) and make/buy a soft palm rest (hard wrist rest may cause or worsen CTS). Also, smaller footprint is better, because you can have your mousing hand closer to the other one.
At last but not least, I doubt you'll find a mechanical ergonomic keyboard priced at about £65. Most decent rubber-dome ergonomic keyboards start at about $100. However, you might be able to get a matrix mechanical point-of-sale keyboard (Tipro, Access-IS etc.) in this price range. Either that, or just buy a regular compact mechanical keyboard (CM Storm QF Rapid/TK, some Keycool, Noppoo Choc Mini etc.). Even DIY solutions (ErgoDox) cost much more than that.