Hi
I know just how you feel, them long days do take there toll and sitting in a classroom on an evening it's hard to concentrate. But it is worth it in the end!
May I offer some advise on books that might help you along.
Electrical Installation published by Heineman, Basic electrical Work by Trevor Linsey. these books cover level 2 2330 and have a lot of good info and some of the calculation. But best for calcs are A J Watkins books on Electrical Calculation, these go up in level starting at basic then getting more advanced.
Cable calcs need to be done using the tables in on-site and 16th/17th ed. but the formentioned books with give you good guidence on the procedures involved
Multi-Meters do the basic tests, continuity, resistance, and voltage and are quite cheap.
I have a Kewtech voltage tester that does everything the fluke equivelent does at half the price (Not a Multi)
Good Luck with your learning, this is great site for knowledge.
KB