Ok… final decision is Salsa Fargo V2 fork at just short of a hundred quid, plus about £30 for fitting at my LBS.
Rigid steel, about 2.5 times lighter than my current sus fork and has plenty of mounts for bottle/anything cages – I don’t have access to frame mounts because I use an Alpkit custom full frame bag.
Something like some fat Kenda BBGs 2.5″ should smooth out a lot of the bumps too.
And also no carbon to worry (unnecessarily?!) about. ;o)
Should make my 20 mile daily commute (road and hardpack) a ton nicer, should be good enough for light trails and track, and should easily be tough enough to handle multi-day trips which generally involve the bike being bundled on and off trains, vans and roofracks.
Thanks all – you’ve been super helpful.