afterdark
Delighted as I would be with YYZ-GLA (and YYZ-SNN) year round, I'm not sure Mrs MarkD would be too thrilled - she was delighted to get off the 319 after 5.5 hours so I'm not sure how well a TA would go down, especially westbound which would probably clock in at 8+ hours! I'll have the BA 744 and the shuttle to GLA, thanks!
Might be some performance restrictions too, given GLA is 5299km GC.
Maybe extending YYZ-YHZ/YYT to GLA could work, as the slower flight might be compensated by a shorter stop/no change and 700km or so less route (GC measurement, via YYT) than via LHR T3 > T1(bmi).
With Zoom's 763ERs as competition it could be tough to stretch a point that far.