I hadn't realised that it is advertised here as well:
http://thorncyclesforum.co.uk/index.php?topic=12305.msg90697#msg90697The Thorn Catalyst has been dropped from Thorns line up, along with their other models of mountain bike type tourers, Thorn is a niche brand known for road and expedition touring bikes, when they had a forage into mountain bikes they found it hard to compete pricewise with all the mass market mountin bikes in the market. Their margins were too tight to find a price point that would sell well and also be profitable, so they decided to drop out of that market and carry on with what they're known for.
All Thorn's mountain type bikes, Catalyst, Enduro, Sterling (Rohloff) and Ripio (derailleur) are well thought of but those who has owned or ridden them.
The 26" Thorn Mt Tura Mk2 Steel Fork - 80 / 100 mm Suspension Corrected fork would be good if you wanted a ridgid fork:
https://www.sjscycles.co.uk/forks/26-thorn-mt-tura-mk2-steel-fork-80-100-mm-suspension-corrected-matt-black/I'd
guess the new price for a Catalyst these days (if they were still made) would be £2500-3000
I would think from reading the ad that there may be some leeway in the price.