Yes, I agree... any rare UK plaque from a well-known club should command at least what the owner of the 500.000 is asking... especially if there is only 2 or 3 pieces known... and, personally, I believe the piece could use a bit more of exposure in ordr to attract the right collector

http://thechipboard.com/index.cgi/page/1/md/read/id/1237747/fs-500-000

Just to give readers an idea; the last two examples of my 1.000 Sporting Club London sold for $1000 (and there were 200-pieces made between 1974-76) each and there are 5 pieces known with one soon-to-be-offered piece breaking out in the $2,000 range... another one-of-a-kind known (no others have popped up since 1994) that I sold for $1,000 was the CHC 10.000 oval... which tells me that you're 100% correct about the 500.000 piece.

I wish I had a buyer or some advice at this time, but I do not.

Better luck...