I think BA's baggage handling at LHR still leaves a lot to be desired.
I took a flight YVR-YYV-LHR via CP (BA is their LHR handling agent) last November. Checked in 4 bags, and 3 came out. The 4th never made it. Some other J pax on the same routing but leaving YVR an hour earlier (YYZ was by no means a tight connection) waited for his and nothing came out. As he was waiting to report the loss, his bags pop out on belt 1 (supposed to be out on belt 5 or 6).
I filed my report. It was delivered by taxi at 7 that evening. Seems BA baggage handling must have sent it off trundling to T 1,2 or 3 as there were no CP/BA flights that came in until 9pm that day.