Hello Alex,
Damian's answer is incomplete and partly misleading, and it needs further explanation.
As a consumer you have some statutory rights as enshrined in the current version of the Sale of Goods Act. (SoGA)
When you purchase new goods (any new goods not just caravans) the 'seller' has a duty under the SoGA to ensure the goods are fit for purpose and free from design, material or workmanship defects. The sellers make a statement to that effect and that is their warranty and position at the point of sale.
If your product has a defect that was present at the point of sale but may have only become apparent
some time later, then that is a warrantable failure, and should under the SoGA be referred to your seller for remedy.
The act uses the word seller, as your contract is with the person or organisation that takes your money, so if you pay cash to your dealer, then they are the seller, If however you use hire purchase then your seller is actually the finance house.
Contrary to popular belief these rights are NOTt restricted to 12 months from date of purchase.
This has summarised your statutory rights.
Over and above this, but in no way obstructing your statutory rights, most caravan manufactures have struck up a deal with a number of caravan dealers to offer extended services commonly known as a manufacturing guarantee (not warranty). This allows you to take you caravan to any dealer who has signed up to the manufacture to have remedial work carried out under the terms of their guarantee.
However, if the problems you are having are serious enough for you to be considering 'rejecting' your caravan as being not fit for purpose, than you must deal with your seller - who ever that may be.