Hello Si.
I promise I don’t work for Trek (I don’t even own one)!
The RLs would be the fork I would buy, if they weren’t only available to manufacturers. I have Talas RL and Vanilla RLCs on two of my bikes – both perform pretty faultlessly. Despite their problems from a few years ago (long story), I won’t use anything else just now.
The RLs are only missing the compression damping from the RLCs, which retail for around £600. The stock setting for compression is effectively decided by Trek and Fox – who frankly, probably know where to set it better than the rest of us.
The 8500 has no obvious weakness in the spec. Even the brakes have the XTR ti pistons specially requested by Trek (helps with the heat) which you can’t normally buy.
I’m really close to ordering one myself – I think it’s a close to perfect £1,500 bike. Looks pretty too!