No harm in asking but I would expect the answer to be no.

UK261 would be the law you would rely on, but that essentially gives you a single chance to rebook. Unfortunately there's no legal entitlement to compensation for the cancellations here (or the reduction in stay length) as the cause was clearly out of BA's control.

What you can clean for is any reasonable expenses you incurred during the outward delay, e.g. hotel costs, meals, transfers between hotel and airport. If you leave near your departure airport then they may suggest that you should have just stayed at home though.

Again, no harm in asking BA for a goodwill gesture on top of your expenses but I would not expect it to be forthcoming.