No problem.Yea, a background in construction definitely helps. I would imagine the course would be difficult without it and I'm not sure of your chances of getting accepted in the course if you don't have an undergraduate degree in the field. It might be best to contact the university first to check this.
If you want to message me your email address, Ill send you some documents to get a feel for it.
In relation to the dissertation, it's left up to the student to decide what to study. Most people seem to study some aspect of surveying/building that they have experience with in work. The dissertation has to include some amount of empirical research which means you have to find a case study on the subject and/or conduct surveys/questionnaires/interview/etc. Obviously, working in the industry would be a great help here in terms of getting access to case studies, industry contacts, etc.
There's no real expense involved in additional reading materials. A lot of what you need is available on the Universities online library for free. If there isnt a soft copy available, they will post you out the books free of charge. They also do inter-library loans if they dont have a particular book.The library service there is very good.