In the midst of an interesting one which I am hoping the great minds of FT will be able to advise on!

Booked SIN>LHR>MAN with Avios using CV.

First leg departed SIN late for no obvious reason and arrived at LHR 1.5hrs late, resulting in a missed connection. Was due to be on a 0650 flight to MAN arriving at 0755. Was transferred to 0955 flight whilst in the air. Due to snow at MAN I am now sat on the tarmac at LHR and it looks like we might arrive at MAN somewhere between 1230 and 1300 so around a 4.5 hour delay.

as this is primarily driven by the SIN leg delay, I would expect this to be compensated but I would imagine BA will try and blame the weather. Any ideas!?