No I hadn't spotted that page of the catalogue, which clearly shows both 'my' seat cluster and fork crown. I've also had a reply to a post on the Retrobike site which reckons the first two digits of the frame number, 76, place it as June 1947. Your suggestion about the headbadge certainly makes sense and I've also just found a photo of a 1949 CB Path which clearly has the same headbadge. So, that just leaves those dropouts. I've just had a close look at them and if they have been cut down, it was done very well. One last puzzle!
Many thanks for your help and to all of you for your suggestions and compliments. All I have to do now is get her back on the road!
John