Maths and me

Thought that I'd best make some notes on what I know about maths, just in case anyone wonders:

1. GCSE - Doddle. Grade A without much effort due to a fantastic teacher and a school that taught in small(ish) classes of similar ability.
2. A-Level - Tougher. Managed the 'mechanics' part ok but struggled with the pure. Grade C. Now wish I'd done the further maths paper as well, the extra lessons might have helped.
3. Degree - Whoops! The first year maths course was taught by a maths professor. To physics students. Lost me in the first lecture and I didn't realize that the stuff he was saying was relevant to the subject until the middle of the second year. B.Sc. Physics with Astrophysics (Third)
4. Couple of Masters degrees, not that much maths content.
   
5. Real life - Improving. Set myself the task of improving my maths skills. Ten years of an hour per day with the Open University later, I'm about to get my second (undergraduate level) degree, B.Sc. Mathematical Sciences (Upper Second)

As far as the puzzle was concerned, I tackled it because it reminded me of stuff we did back at GCSE level (almost 20 years ago...). I resorted to more advanced stuff for the later parts of the question though.

So, I've done a lot of maths, and I use it quite a bit for work, but I'm no maths genius. It's something that I have to plod though slowly and check my working. Hence my comments about not expecting to get the whole of the puzzle correct.