I would look at it this way - if you are a DH focused collector, assembling a collection of iconic bikes, you’ll need a San An. Now, the frames do pop up fairly regularly - but this is an early one, with a Risse, the correct forks and the correct brakes - and it’s good to go with a high quality build..
As they say “find me another”.. It could takes someone years to replicate that.
Pricing is subjective, but it’s gotta be worth £2k to have that package in one hit. Mid-90s stuff like Super 8s, thermo LTS DHs in quality full period builds are being touted at these kind of prices. The San Andreas has more rarity and at least similar icon status.
Would be interesting to see what it would do on eBay, though that’s evidently not your plan.