Annual service - DAMP Advice please!

Hello All - Firstly apologies for the long waffle in this post - We were new to caravanning last year and bought a 2007 Ace Jubilee Courier. Had some great times out last year and loved every minute and cant wait for this years outings. Last month we started to get the van ready for this years trips which included a service although we had only purchased 8 months prior and came with a service. You can imagine our shock when during the service we were told we had damp :o( I've read a lot about vans and damp and its par of the course however the van is riddled throughout with no real area of where we can see any ingress and we were quoted 2000.00 to repair. When we bought the van we were told we had 3 month warranty and that things like damp checks were performed to ensure no issues when it left the dealers. We took all this on face value as why would we need to get it rechecked as we trusted what we were told. My question is (from any caravaners who may have gone through something similar), do we have any comeback on the dealer given we've only had it 8 months and are getting in some parts damp readings of 80% or am I just needlessly hoping that I have a case? Thanks in advance