Rightfully, this has caused some confusion much like it did me and BA although there was probably a better way to explain it.
The language barrier was with the adult who was travelling on the earlier flight and didn’t speak English very well. She was the only one trying to check them in at this stage - the boy was stood back from the desk with his friend.
The staff asked if I understood what they were trying to explain as I was just waiting for the lady checking me in to return. The adult couldn’t understand what the problem was so I asked the boy if he had anything signed from his parents to which he said no and then he begun talking in French with them and after that they come back to me asking if I knew them or not, again I said no and at no point agreed to have my booking linked yet seemingly they did.