Thanks for the tips!^
I'm coming in on UA at T1, scheduled arr 2018, and then on to T5 for BA 298 dep 2205, in CW.
As I'll be going to the airport from work directly, with no time for dinner, the pre-flight dining will be important.
Question: Assuming I won't be able to check my bags at YYZ with UA to interline with BA, I'll have to get them, lug hem over to T1, check them in again (will have OLCI'd but not PYOBP'd). Is there a First check-in at T5 for BA? That should at least cut down on queuing time at the BA desk.
Just hope all the timing and security queues will work out!