I think you should get a DJ and an Enduro bike. Enduro bikes these days are so capable and are becoming so pedal-friendly, it should be perfect for XC. Dirt Jumpers, are crazy fun and they really increase skill on a bike. My jumping skills took off after I visited my local bmx trails.
Check out Bird Bikes since you are in the UK. They have exactly the type of bikes you're looking for and have a pretty good build a bike the way you like program.
I'd probably get a long-travel enduro for park days, something like a RM Slayer or SC Megatower, and for the more "XC-ish" rides I'd get a aggressive hardtail, my top pick would be the Chromag Rootdown (or the Chromag Primer is money is no object, or if you're the type of person to care about "handmade in Canada" things)
Could always try a Guerrilla Gravity? (dunno if they ship overseas from the US) but the seatstay kits could offer you 2 different bikes with the same front triangle. I think it would be cheaper than buying 2 separate bikes?
Didn't know that, might be worth a look into.
Yea check it out! I'm going to try to get a test ride on one soon as that is the main reason I want one. Having a nice trail bike and an enduro bike without having 2 actual bikes would be awesome. Got it covered from XC to some gnarly DH stuff if you wanted!