I thought BA/IB interchanged freely on Spain-London routes, just like BA/AY to Finland. Why then don't they codeshare on AGP-LHR/LGW routes? I have an IB ex-US flight and would like to fly AGP-LON but they are forcing me through Madrid......

Just noticed that all the ex-AGP flights are full, but eitherway, even Expertflyer doesn't give you the option....