G68SL and G61R are still supported by Meridian and will be upgradeable to the latest software version (1.5, I think) which updates the Direct and Stereo DSP functions. I think they can still be be upgraded to a linear power supply as well (but that's an extra cost). There seems to be a number of G68ADV units on eBay at the moment, with some from known suppliers at sub £1k.
568.2mm is still a good option at a lower price, particularly when adding a HD621 as the 500 series units seem pretty solid and reliable.

Brian

Main: G65, MD600 Sooloos, MC200 Roon Core, MS600, 210, 218, UHD722, DSP5200SE, DSP5200HCSE, M6 & DSW.2
System 2: AC200 MS200, WiiM Pro+, M6.
Other: DSP5000 (96/24v1), DSP3300.