Take a look at the Genesis Altitude Range
There’s the Altitude 10 that comes in just under £1k with a 520 frame and Deore/SLX kit and Rockshox Recons, or the Altitude 20 that has a Reynolds 853 tubed frame but pretty much the same kit, for another £150 or therabouts.
I’ve got an 853 Altitude Frame that I built up into a custom specced bike. Very impressed with it. First hardtail in a LONG time I’ve liked (I’m very much a full sus convert normally). It handles brilliantly, is pretty light, has that nice “steel feel” and is designed to work with a fork between 100 and 130mm of travel. Also a fair bit lighter than the Orange P7. Great as an allround trail bike.
If I was looking for a £1k race bike, then as OrangeChammy says, would look at a Boardman Pro, but if not, then my vote is definitely for the Genesis.
Though also worth looking at the On One 456 complete build if your budget will stretch to about £1200.
FWIW, Chameleon is a very direct handling frame, but the single most unforgiving one I’ve ever ridden. 100 yards on one was uncomfortable! They’re also about £500 or so for the frame only, so well out of budget.