Any idea of sensible price for used Tremoverb 2x12 combo UK?

Hi guys, I was told this may be the best place to ask this - what's the going rate for a used Tremoverb combo in the UK these days? I've seen two recently, one for 1200GBP and the other at 850GBP. Both seem high but it's meant to be a fantastic amp of course. Should I wait for a lower price or does 850 sound fair for one in good condition? as they've been out of production for so long they rarely come up, so it's harder to gauge the price than on some newer models.