We’ve just been through all this with my DS
He was lucky in a way that he knew his main interest was aero, he was always interested in this aspect, though for a while he considered robotics
What we learned is that the entry level for MEng is higher, so whether to for for BEng or MEng would depend on grades he is likely to get.
Then, look at some Universities such as Bristol which offer combined option of Mechanical Engineering with Electronic Engineering. This was DS second choice
He spent ages reading course descriptions. Let your DS take his time and see which areas excite him most.
This year there were lots of places in Clearing for Engineering degrees in Mechatronics and materials engineering (both look slightly undersubscribed so easier to get into)
FWIW my DS was working at AAA but got AAB in the end. He had applied for MEng asking for AAA…. But the university still offered him a place. I think this is not unusual? Lots of universities request higher grades but in reality accept a bit below what they say.
Still, with hindsight, he should have probably applied for BEng as safer bet! Ideally a 4yr ;BEng + year in industry) and then you can always still do the masters
Just my tuppence worth
Good luck!