A-levels are not everything
I have to say that A-levels are not everything and that a good degree has more weight when employers select candidates. I have 1 A-level at grade D (which is not great), but a 2:1 degree. A-levels are very different, and if you pick the wrong ones then you are going to struggle. If A-levels are not for you then i would pick an alternative course that Universities accept.
I have applied to the CTC McAlpine & BA cadet schemes and have passed the application stage on both.