I seem to recall that Wardair sold their own tickets (although as you say rog it may well have been through a wholly or partially owned tour operator subsidiary for legal reasons). I think that their UK head office was in that large octagonal building by East Croydon station and that they had a large sales outlet in Eaton Centre in Toronto.
I remember seeing a Wardair 747 at Birmingham airport sometime in the 80s. The flight continued to another UK airport - it may have been Cardiff before routing back via BHX. The 7,400 ft runway must have been just long enough for a flight to YYZ but I would have thought rather tight.