Usually the Flight Deck briefing is the most informative area:
[s]https://www.flyertalk.com/forum/brit...3-edition.html[/]

But yes, if the LH service is a go-er then I would expect BA to rebook on to that instead, or even the BA App may propose it. If it is declined, which would be unlikely, or it's difficult to contact BA, then they are on the hook under the LE v TAP judgement.