OK, thanks for the feedback – esp. retro & stato. Comment regarding rockgardens is very relevant, as that's the sort of terrain I'm finding the fork (Rev's) gets out of shape. The worst places tend to be riding at moderate to fast speed where there are fist sized rocks embedded into the trail surface – depending on where the rebound damping is set, fork starts to feel either solid or too 'pingy'. It's a shame because the back end of the bike (Pace 405) handles that terrain really well – and the fork is fine elsewhere. But, as I live in the Peak District, there's quite a few rock gardens!
So, if I've got this right, the PUSH damping is speed sensitive, so it'll avoid having to stop and re-adjust the damping (which I normally find a bit hit and miss)?