Slingsby
FWIW. the DC6 is a "piston" a/c [TOTALLY] different sound.
When I woz at Brum [1969/70] the VC9 Vanguard LHR-EDI??? was very noticable
I live East Manch, and the DLH/BCS L188/Electras were very obvious from EMA-EDI in the "Early hours"
we aim to please, it keeps the cleaners happy