As above, there's really a substantial list of top tier unis for engineering. For aero specifically this is my list, with any notable differences that I know of in brackets:
UWE (relatively low grade requirements), Surrey (Space + good extracurricular projects), Southampton (Space), Sheffield (Space + more variety than other Aero degrees + good extracurricular projects), Strathclyde (Space + good extracurricular projects), Glasgow, Leeds (Very Mechanical focused), Imperial, Bristol, Bath (top Formula Student team), Manchester, Nottingham, Loughborough, Swansea(relatively low grade requirements), Oxford (General), Cambridge (General), Durham (General)
If you go to any of those then a good career is in easy reach, either in industry or academia. If you're an international student then you might want to be more choosy with which universities have the stronger brand name, but even then you won't notice too much difference in career prospects between say Sheffield and Oxbridge.
Also the theoretical nature of Oxbridge engineering degrees is just a different approach, not necessarily an advantage or disadvantage in industry. However academia is generally a bit sceptical of Oxbridge graduates as undergraduate Oxbridge educations supposedly don't prepare you as well for research careers as other universities. I'd also disagree with equating theoretical and PhD, the theoretical part is really a small aspect of research and most of it is applied, just not in the same way as industry does it.
I wouldn't worry about not getting a qualification out of any 4th A level you drop, as soon as you get to uni even the grades of the 3 you do complete really don't matter anyway, do it for the learning which will be much more advantageous at uni and potentially beyond. I'd say do Maths, Physics, Further Maths and a language as knowing a language will really improve your uni experience and potentially graduate prospects, but it's up to what you'll enjoy really, don't do FM or a language if you would prefer to do something else, neither of those are necessary.