Lugs are Crespera and appeared on a wide range of frames. Is there a frame number somewhere? Bottom bracket, behind the seat on the seat tube or rear
dropouts.
Is there any chrome on the last 6-8 " of the forks? If there is then its more likely to be a Corsa as the Grand Prix had no chrome. I'm assuming it has a brazed on centre pull hanger for the rear brake?
on BB serial number appears to be 1 and then ar tight angles WES004188
There's a semi circular braze on piece for back brake pull through
Not sure about forks at moment as they were painted light green...have rubbed some off but it could be plain steel
Frame number is W = Worksop (Carlton), E = April and the third digit should be a number which is the year starting 3=1973. Could be a 5 that looks like an S so 1975.
Is there any clue as to the original colour? Inside any of the tubes? Light green if original would tend to suggest a Corsa if chrome ended forks.
The Continental had side pull brakes so no braze on rear brake hanger although that did come in Aqua Green as well.
Carlton used this frame for a wide range of bikes, even the early Raleigh Europa