MGB 1 for sale Very rare registration plate. A similar plate - "MG 1" - was once proudly on the blue MGBGT owned by John Thornley. This auction item was spotted for the V8 Website by Keith Belcher. Posted: 230106 Silverstone Auctions Saturday 25th February at 11.00am GMT Registration number MGB 1 on a Retention Certificate is up for sale. Link to auction website Guide price: £40,000 - £50,000 plus buyers premium of 10% plus VAT That's 12% including VAT John Thornley outside his home in Abingdon with his MGBGT "MG 1" - very similar to "MGB 1". Lt. Col. John W. Thornley (1909-1994), OBE was one of the founders of the MG Car Club and served as its first Secretary. Later, he went on to become Director and General Manager of the MG Car Company.