Reading all your posts @mrsconradfisher my view would be for your son to take a gap year, get some relevant career experience (do personal training/exercise instruction at a gym, for example?) and re-apply with grades. And an explanation - maybe from his school teachers' references - that it's a small low-achieving school, and he is one of 6 going on to HE, and that they don't (as a matter of policy) predict A Star grades. These are the kinds of things we academic staff involved in Admissions are trained to look for.
I can understand why his school won't predict A stars if they have so few students going on to HE - they just don't have the context & experience to predict work at high levels, but if he achieves one, then he'll be in a very different position.
If he feels Birmingham isn't right for him, it'll cast a pall over his degree - there'll always be that "What if?" And the degree he wants to do is so specific.
@poetryandwine mentions Lancaster - I used to work there, lovely university, great people, great city - but I'm not sure they do such a good line in Sports Science (although the Roses every year is hotly & expertly contested).
But if he's really, in the pit of his stomach, not wanting to go to Birmingham, he really shouldn't. And if he was rejected by Loughborough in this year's UCAS round, and the course he wants is not in Clearing, I doubt whether there's any point in pinning hopes on persuading them.