I can recall the Herald being used for a while LHR/GCI. Was replaced then by the F27.
Mail was seat loaded in rows 1/2 with a net used to secure it.
Where possible pax were not to be seated in row3, the net went over the seat backs of row 2.
Given the loads were usually always pretty full most of the time that was unlikely.
Two rotations per day, morning and evening.
In the event of being unable to get into GCI (WX) I believe the operational instruction was to return to LHR rather than divert to JER. That way the flight was cancelled due to "weather", originating pax were rebooked for next available with HOTAC only required for transit pax.
Struggling now to recall the flight No's, think it might have UK131/132 & UK 136/137.
Also recall a Captain Haysom (Heysom ?), think he was either fleet or training skipper.