Forget about compensation for now.
If you haven't already called BA and told them to protect your LHR-HND BA7 flight tomorrow and advising them you'll be making your own way to Heathrow, you need to do that as soon as you can.
Spoken with them. They’ve removed the MAN-LHR element and we’ve checked in for BA7. I stressed several times that I didn’t want to lose that flight by taking matters into my own hands.
I asked the initial question here whilst on hold to them as I wasn’t sure how long they’d take.
Will they cover incidental costs?