I know BOAC took on some Pratt and Whitney powered 707-336B/Cs towards the end of the 1960s/early 70s - I belive Hotel Uniform was an ex-Saturn bird.
LHR-SVO-TYO and LHR-ANC-TYO were 320B/C specific routes, however I think BOAC had more aircraft than was needed for just these two routings.
Did BOAC have any other routes specific to P&W 707s, or did they also operate alongside Conway 707-436s?