Maybe my eyes were deceiving me (getting old now) but if not then I just saw a 53 Plate Blue Wee at the Swindon Stagecoach depo.
I know the Wee was released as a 2004 model and there are a small number of 04 plates around. Mine is a 54 as are most of the early ones.
The model was released in early 2004 so a 53 Plate is possible. It could be a private plate, but the gorgeous silver frame dates it to 2004 anyway.
Will see if it is there again at some point.
https://www.howmanyleft.co.uk/vehicle/suzuki_dl_650_k4