Very nice offer, I do need to get some spares but having a GTN I need to refurb them to the correct colour anyway - so I would rather either brand new for that price or a set that is not curbed but just tired and needing a refurb, else its getting rather expensive!
My understanding is that the last of the new wheels left the factory a decade ago at £600+VAT a wheel so £500 to have a functional spare is cheap insurance in my book (even more so on a £100k car like yours!).
Brian Dunton down on the south coast is having one off me in January, and i'm keeping at least one for myself - but there are two left at this point.