An AFA 85 was snapped up off of ebay this week with a 450 GBP BIN and went for less than that as the seller accepted an offer. Last week an UKG 85 with COA went for about 630GBP. I think you could get closer to the 550 mark with it on the bay although you may have to offer it worldwide. There seems to be particular interest in the AFA graded ones (go figure), and with most of the sellers wanting a minimum of a grand for them I think you could do well on the open market.
That said though I'm not sure if you're buying or selling and I'd imagine things would be a little different for a private sale.
Anyway, all the best with it.
Ian