What I found on Classic Lightweights was perhaps the lugs are Ekla. The seat stay caps too were provided by Ekla.
Edit: yes I see now they are Brampton lugs.
The Gran Sport derailleur is 1st generation with the built in cable adjuster.
So the parts are later than the frame. The fork crown and fork are a mystery. I cant find any Bates' with the simple fork crown mine has or the round fork blades. Perhaps a replacement? By Bates for sure. Or is this a characteristic of earlier Bates bikes? I think the top tube cable guides and downtube cable stops were added at a later time as well. It was used as a 10 speed with front derailleur.
Anyone have an open C Cathet
Ynowmpy shift lever in their parts bin? I am missing the lever for a front derailleur. The 5 speed set up on the bike now is sort of poorly executed.