Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
I would also price a BOS-LON//BCN-BOS "open-jaw" cash ticket, as it might be reasonably priced for travel in March. You could still use BA Avios for the LON-TXL leg.