Advice please from the cognoscenti. I have Business tix: DUB-LHR-MIA-MCO out and MCO-ORD-LHR-DUB back. BA has cancelled the first leg, DUB-LHR but the remainder of the booking still shows in MMB. Does this mean that I MUST find an alternative DUB-LHR to commence the trip; or could I just start out with the LHR-MIA; or is the entire trip imperilled and I must rebook everything?

Similarly, I have CE LHR-BLQ round trip with the outward flight cancelled. We can get to Bologna by other means but can we pick up the return leg of the round trip to get back to UK?

Thanks for valued advice