Originally Posted by
Often1
OP - Please clarify. Are your tickets LON-SEA with a connection at LAS or are you on separate tickets: LON-LAS and LAS-SEA? It sounds like the latter, but it's important to be certain.
If the latter, your final ticketed destination is LAS and BA will fly you there. If you already have your LAS-SEA tickets, what is the plan for those?
Separate
First Ticket: EDI-LHR-LAS // YYC-LHR-EDI
Then single LAS-SEA