Paul
Not sure if you've been here
http://www.microscopy-uk.org.uk/index.html
But this site should help you. The articles by Dave Walker are excellent.
It's worth considering a digital eyepiece so you can capture the images on your PC otherwise its back to the drawing board so to speak.
Proper setting up of the microscope in the first instance is vital and far more important than spending large amounts of cash on a microscope which will spend a lot of it's time under wraps (and that's very important too!).
If you intend looking at fungi spores you need to be looking at least X400 magnification and sometimes X1000.
Good luck in the minefield
John