Crampdin13A is right. And I didn't even mention the UD which was one of the best overnight flights I've ever had
Dinner YYZ sleep in 30 mins UD through LHR in no time
But for European over nights if you can go direct on AC I would.... And even seriously consider it for some connections. other than the arrivals lounge at LHR which you have to go airside to enjoy I would avoid the LHR transfer. I actually quit like the old BA 767's crews have been great and it's a small cabin too
My only overnights on AC to Frankfurt Copenhagen and a couple of others were all as a single traveller not with mrs ACS and AC is not set up well for a couple who want to shat a bit