Originally Posted by
gaelflyer
One thought, check if AC still fly via Shannon (the Shannon stopover is being discontinued) and go London- Shannon instead, giving you some more time.
As I understand it the OP has already booked the long-haul flight, and it's a cheap flight so it's bound to be "no changes no refunds" - so switching to Shannon is unlikely to be an option.
With a non-changeable/non-refundable ticket and no baggage interlining I would not rely on connections of less than about four hours, regardless of who is running the connecting flight.
BTW, Welcome to FT,
njm!