MrJBoy

We were booked on UA934 LAX-LHR on 2/12 and then UA938 LHR-BRU on 2/13.
When we arrived at LHR at 12:36PM which was already 1 hour 7 min delay, we were told that our next flight UA938 LHR-BRU (scheduled arrival at BRU 3:35PM) was canceled because the aircraft didn't come from SFO(?) due to mechanical problem.
When we were deplaned, the GA gave us a BP (BA404) which departed at 5:45PM (5 min late) and we ended up arriving at BRU at 7:51PM (only 1 min delay for BA404) compared to 3:35PM by UA938.

At LHR we asked the GA about earlier flight to BRU, but he said the next flight (I'm not sure which airlines) would depart at 12:50PM.
Since our flight UA934 arrived late UA couldn't get the 12:50PM flight for us, arghhh.
So we had to take the BA404 5:45 departure flight...

My question is should we ask UA compensation?