John, the Bormilathe inhabits the dark world of the esoteric and unusual and therefore like antiques is difficult to price as value is generally in the eye of the punter.
Seen 2 come up on e-bay in the last few years when I was after an example. One I am sure sold for about 550, It was fully loaded as yours is. The other I don’t think sold was not quite as complete.
I coughed up 200 for an incomplete short bed version (particularly wanted a short version), otherwise would have considered the one I saw on the Bay, which I rather regret not going for now. I paid another 200 for substitute change gears, faceplate, motor, countershaft and it still needs a cosmetic makeover (although mechanically A1). Also still requires a boring table, which is really a fundamental part for this machine.
If you are patient, I would have thought realistically, somewhere between 550 to 650 should be possible depending on condition, degree of originality and extras etc. but you will likely be selling to an aficionado of the arcane and obscure.
+1 for the Lathes UK site for sales, it is a paid for site but generally attracts people who at least have some idea of what they are looking for and associated issues (i.e. the moron factor is is minimised).
E-bay Ok but not as an auction. Put it on at the price you wish to get as ‘buy it now’ and ignore the half wits asking if you will take ten quid for it, scammers wanting to pay £1000 into your bank account for later collection etc. Be prepared to answer sensible questions via ebay messaging, cumbersome, but keeps you safe). Dont dismiss gumtree, but beware of scammers. As I recall, both examples above were on e-bay for a considerable number of weeks, so you may need to be prepared to take time. If ‘twer me, I would try and hold out for 600+, but for many reasons, times are not what they used to be in the old Britiron market.
No experience of fakebook market, but am reliably informed it is something of an idiot magnet.