This is my post from july, Very frustrating, I do think BA are trying to get you to buy the seat at a cost
Came back on mco- lgw last month in J with my wife and 2 year old daughter and guess what? checked seats at -72 hrs ,daugter put in isle seat, wife in aft facing seat next to her although couldn't reach her without standing up and my self 1 row forward in isle. but what really annoyed me that all other seats around us were showing available for a price.
At -24 hrs guess what all empy seats allocated to others, and check in staff said there was nothing they could do.
luckly a single traveller seated next to my wife was happy to move,but why wasn't this single traveller put in my seat originally, he said he didn't even on line check in??