The OU; the Open University. It's a British university founded sixty or so years ago with the intent of widening access to higher education. Their campus is centred in Milton Keynes, a bit north of London.
I took a Masters in Maths with them and it was brutal. Serious exams are a youngster's game. I got a glimpse into why so many Cambridge wranglers were also serious atheletes.
Search for "Open University MST124" or similar on www.ebay.co.uk or www.amazon.co.uk. There seem to be plenty of copies of 124 available on both at the time of writing.
The courses the comments refer to are the level 1 courses listed here: http://www.open.ac.uk/courses/maths/all-modules
The text books are the texts for these courses. I don't know if you can get the books from OU without registering for the courses.