ex eu reward flights. is it possible?

as we have to pay cash to fly BA from EDI to get to london for our reward flights normally, I was wondering whether its possible to book a reward flight from an EU location (via london) and simply fly there from EDI instead.
ie. AMS > LHR > JFK or DUB > LHR > JFK etc.
I wouldn't mind if the eu leg was cash or miles, but it would have to be on the one ticket with the Trans atlantic for protection and to avoid APD.
Obviously this is simple with CASH but how about miles?
Is this possible?
ie. AMS > LHR > JFK or DUB > LHR > JFK etc.
I wouldn't mind if the eu leg was cash or miles, but it would have to be on the one ticket with the Trans atlantic for protection and to avoid APD.
Obviously this is simple with CASH but how about miles?
Is this possible?