This registration is not listed in the last published edition of the London Douglas Motorcycle Club Machine Register. However, that does not necessarily mean it no longer exists as although this lists 402 of the original 1510 examples of Dragonfly manufactured (a very high survival rate for machines not produced for 50 years), the list is known to be incomplete as some machines are owned by non-Club members whose details have never been included. Also, it is some time since the last edition was published and no doubt new information will come to light with the new edition in preparation. You could check with the DVLA at Swansea in England and they will inform you whether the number is still in being. A check on a motorcycle number I made a while ago revealed that the number I was looking for was now on a car.