Lovely detail, thanks for posting, I saw another thread about the lugs and dropouts on other frames of the period and wondered whether it was possible to identify these-----
a most beautiful job with it, what a fortunate cycle to have fallen to your hand!
frame -
three tube 531 plain gauge
dropouts Cyclo (of England)
bottom bracket shell, may be Agrati N. 000.8507
fork crown Agrati "ROMA" pattern N. 000.8028
Ernest employed a fair amount of Agrati during his time with the raptor
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The dropouts are incredibly thin. I wish they were a little more exotic but this will have been an affordable bike at the time. I note the falcon catalogues of the era also mention these parts, which seems odd today given the obsession with ever more technical groupsets.