Well, I did a bit more tinkering..... and made it worse. Lol.

Made things a bit "grainy". Is this what compression is, I wonder? Wish I'd written down the settings I used this afternoon. ne'er mind it's not too bad at all. Quite playable. I'll have another tinker tomorrow. I'm on annual leave. Time to play with my toys.
@TheOracle, I've used similar in game settings to the ones you posted above. Admittedly quite a few of mine were on lower detail prior to seeing yours. So I upped them to see what happened with my 3080 ti. Surprisingly the gameplay was still quite smooth. I've just made it a wee bit poorer/grainier than it was earlier today.
@melmac, so far I think 700 Bitrate, 72fps and 1.3 res seems ok from what I find. It's not been a scientific experiment though. Just whacked in a couple of changes and see what happens. (I didn't have the patience to do one change, restart, test and repeat. I know, I know I should known better than to change two things at a time).
All in all I think ithe Quest 3 has been worth it for the money it cost me. £96 discount from the Berry site, ten quid from Topchashback and a bit of cash recouped from selling my Q2. Net payout £230. Can't complain.

. On the other hand, now I'm seriously toying with the idea of splashing out on a 5800x3d to replace my 5600x. No way am I going to get a 4090 though. That rabbit hole is calling me but not loudly enough to drop a grand and a half on another gpu.
What is it they say? The difference between a man and a boy is the price of his toys

.