I used the online Bristol database, and for my 1st set of exams back in October it was very reliable.
However, for the January set, there were at least 10% less questions appearing in the exam from the online database. This is only using V2, the questions could well of been in V1.
Fortunately, I revised hard and didn't rely on the database, so still managed a 93% average, but I think those who rely entirely on the online question bank will begin to suffer in the future.
So, to finish an ATPL course, distance or residential, will take a lot of dedication, and a lot of time spent with textbooks.