Hi,
I did finished my ATPL's just under a year ago, but did them at the CAA headquaters at Gatwick.
I would strongly advise against making too many markings on your charts before the exam...one of the guys on my course was chosen to have his charts looked at, along with another person (normally 2 people chosen at random) and he had marks on his charts from some of the exams and examples we'd done in class at our flying school. The CAA didn't take too kindly to this and failed him for that exam and he had to re-take it.
With regards to the questions being similar to the question bank...myself and a lot of the people I know, have used the Bristol database and we found the questions in the real exam to be identical, if not the same as the ones in the database. I have been told, however that the CAA have added some new questions and I'm not sure if these appear in Bristol or any other databases so you might want to bare that in mind!
Good luck with your exams,