This could well make less than that £600: http://www.ebay.co.uk/itm/Humber-Sceptre-/190954654454?pt=Automobiles_UK&hash=item2c75c8caf6 and seems to actually have the majority of the metal it started off with present.

As an aside, do we have any Maltese Hunters: http://tinyurl.com/nrr8wxf at IMCDb.