As a full stop on this thread, I looked at a second hand Commencal Meta but there was a couple of things made me nervous and the guy was wanting too much money (£1,400 - for a 2019 full sus bike that had never a suspension service, as an example of things that made me nervous).
Lots of shopping round and considering options later, I found an Orbea Occam H30 for £1,900 delivered - about £700 off retail. TrainerRoad users' bikes - #2399 by swgregg
I’m delighted with it other than it needing a new saddle (I’ve got one in the spares box) and the 175mm cranks are a weird equipment decision in my opinion, so will be looking at an upgrade to 165mm SLX cranks to keep my options open for a crank/spider based power meter later. The wheels are solid but heavy so will look at an upgrade for them in future too.