This 20TA Scottish frame No 9085/TA engine number 372B1727 (from Bond Minicar) sold at H&H Donnington Auction back in January this year. Not sure why it has a 'T' (1978) registration CHN20T, would have been appropriate on a 20T but I did not think DVLA allowed later numbers, the bike is a 1958/9 model It has been untaxed since 01 September 1987, Sold for £2072.
Was previously sold by Bonhams Dec 2016 for £1092 inc premium. https://www.bonhams.com/auctions/23599/lot/209/