Bristol do have a website at:
www.bristol.gs
Their forums are also available to anybody, and can be located at:
http://www.jals.co.uk/forum/index.php?
As for doing the progress tests, they are meant to be done closed-book, i.e. no reference to the text.
I would try and do each subject in a frame as if you need to pass the progress test without reference. i.e. avoid just reading the text once and then doing the progress tests. At the very least try and make sure you understand the concepts before moving on. You will find that you must do this in subjects like Met, Gen Nav, PoF, Perf and Instruments.
There will be the odd time when you have to look at the texts; certainly it is likely you will need to if you fail a particular test. I treated each test like a hurdle - I didn't move on to the next subject until I had gotten my 75% +.