Is it possible to do a custom routing with Avios vs just the results displayed. For instance instead of LHR-BRU is it possible to get LHR-MAD-BRU (award availability is on each segment)? Do I need to call in? Can I do it online? Or can agents only see what I see. I have been doing a lot of booking through Aeroplan which allows custom routings and just wondering if I can do it with BA.