I don't know which foundation programme to apply for, please help me out!

a) have you considered Southampton? They're very highly considered for engineering, and offer a foundation year to prepare for such. I did the Science Foundation at Southampton and the engineers seemed pretty happy with their course, although I gather it was much more intensely programmed than ours. You could take a year out and try applying there. Also, as a side note, I believe Queen Mary is fairly well regarded at the least in the field of Biomedical Engineering; not sure how other courses rank up specifically however.

b) I'm currently studying Electronic Engineering at Exeter, so I can probably offer some advice on that front:
Exeter is not currently considered an elite engineering school/department. However it is generally well reputed (and this is increasing each year if the administration are to be believed).

The electronic degree is generally more angled towards communications and computer engineering type topics (think digital signal processing, networking and internet technologies, and communications engineering in addition to basic analgoue and digital electronics, microprocessors, and programming) than the more electrically inclined power engineering options. You do a course in EM waves but there it doesn't really deal with engineering for power/energy or device physics so much. If you're more interested in the Physics side you could take an optional module in third year in physics (I did this), and the physics department is pretty good.

Outside of the curriculum itself, there are a number of other opportunities. As mentioned, the physics department is quite good, particularly for exoplanet research in astrophysics and graphene stuff in general physics. The graphene group is cross disciplinary across engineering and physics, and so if you have any interest in this there is scope to work on this side of things in your third year project or as a summer project. Every year there are 3 EPSRC funded summer vacation projects in engineering (physics have about 6 I think). While one might think they're quite fiercely competed for, the year I did mine only two people applied, myself included. So that can be a good option for beefing up your CV and getting paid to do so (I got paid about £2100 over 10 weeks, so not masses but enough to cover your living expenses and probably then some at the least for that period).

One of the benefits of electronic engineering at Exe however is that the degree programme (that is to say, post 1st year where all engineers take the same modules) is fairly small; there are usually only 20~ people doing electronic (less in previous years I gather) so the lectures for 2nd and 3rd year electronic modules tend to be fairly small and so the lecturers, for example, tend to actually know who you are (which can be helpful for 2nd/3rd year and/or summer projects, as well as references after you graduate).