MGF 418 was owned by Margaret (Maggie) Ward in the 1950's and that is probably her in the above photo. She wrote a letter in MPH 608, September 1999 about her Vincent ownership in which she mentions the person she sold MGF 418 to then blew up the engine trying to go fast and so ended up with the bike "as a heap of spares". MGF 418 is not on the UK DVLA system so probably long gone.
Simon