Here's me gleanings from my many years of marketwatch...
£250 is about right for the tolex models.
There have been some sacrifice prices leading to low expectation, I think.
These were never cheap - nor overpriced - new.
Carpet - lower new prices, cheaper drivers, so less.
£150ish rough, £200ish v. clean seems about right.
Maybe +£25 for the 210, as this has emerged as a 'wanted' format.
+ or -, depending on distance/delivery and level of 'need' at either end.
Then - factor in time spend/waste in 'any pics'/deemos/trials/comparisons/hemming and hawing/delaying/payment.....
Determines 'hard' and 'soft' pricing.
Bottom line has to be cost of drivers - 8ohm 200w celestion 15 is £50 min, 75w Celestion 10 £30 each min., horn £20.
£100 salvage value.....