I would've thought that YVR-YEG-LHR would work, but it doesn't appear as an option. Possibly this is because my ticketed itinerary is LHR-YEG return? I'm making a change to incorporate a quick jaunt to Vancouver, and for whatever reason YVR-YEG over those few days is crazy expensive.

And no - flight passes not an option for me. My amount of travel is unpredictable and not paid by one organization.