Ds1 wanted to go to Bishop Vesey's and ds2 wanted to go to Queen Mary's. I mean, they went on and on and on about it.
And I ignored them both - they're both happy at Camp Hill now
It was only on results day that I actually understood just how much they wanted CH and how happy they were to make a place. But they were so afraid they'd not made it, that they stubbornly clung to wanting schools that they thought they would have made a place at, having found their exams easier (BV was a separate exam for ds1), in order not to feel they hadn't 'made it' at the end.
I hope that makes sense. Sorry if it's a bit garbled.
If your ds feels that the Birmingham exam hasn't gone as well for him, this insistence that he wants QM, and mentally making it seem a much better school, could be a coping mechanism.
Personally, I wouldn't listen to a 10 year old at all. There's all sorts of things going on in their head (it's a mystery that frankly gets worse when they hit their teens

) .... use your own experience and judgement.