Bailey ranger / discovery - damp issues?

I am interested in buying a Bailey Ranger / Discovery 4 berth. I like the end washroom layout, and side dinette converting into bunks. I've done a bit of research, and there have been some posts that suggest that damp has been a problem in some of the later models (2004-7). Are the earlier models e.g. 1999 better to go for? Any andvice would be greatly appreciated :)