BA, like any airline, can and do switch planes at any time for multiple reasons, some inexplicable to passengers.

My wife and I are off to New Orleans in June, when we booked it was a 787-8 with old club world; a few weeks ago I noticed our seats had been moved from row 3 to row 8 and we were now in the middle of the cabin. The seat map shows a 787-10 but there is no plane type showing in the booking. Of course, no notification of change.