Warranty help needed please

Hi, am looking for come advice.  We bought a 2010 Elddis Crusader Superstorm last year privately, it is our first caravan and we love it.

The only documentation we had was the log book and all the instructions etc.  Anyway I managed to get the CRIS document sorted, but as we hadn't been given one from the previous owner CRIS had to write to them to confirm they had sold it on.  Now on to the warranty, Elddis have told me that's more than 3 months have lapsed since we bought it they can't transfer the warranty, more importantly the 1st service wasn't done within the required time and so it has become completely invalid -  am beginning to wonder if this is why they didn't give us the CRIS document?  

So here is my situation, very worried about water ingress and as we have lost what would have been three years worth of warranty, is there a warranty I can take out and is it worth it?  I have heard that water ingress can be very costly.  We are feeling very annoyed with ourselves that we didn't pick up on this at the time of purchase, at least if we had gone to a retailer we would be able to go back but a bought as seen sale (it had been serviced 2 months previous) we a bit stuck with it.  We did a lot of research on the product and they have been caravaning for years so expected them to be genuine enough about the whole thing.  It's going for a service tomorrow which we are slightly apprehensive about, just hoping the warranty isn't the only issue we have.

Any advice would be very welcome, thank you.