The dealer should have notified you that the stability control ATC would be fitted at a later stage as none available at the moment. This is reason enough to reject the caravan out right as it is not as described.
If the caravan is on finance your contract is with the finance company and not the dealer and you need to notify the finance company immediately of the issues. If not on finance then contracts is with dealership. Keep as much as possible in writing to form a paper trail. Unfortunately with a telephone call you have no proof of what has been said. Dealers will normally reply by telephone as they are aware that there will be no record. Always insist on something in writing before agreeing to whatever they are proposing.
Secondly the faults. If within the first 30 days from delivery as OC correctly states you have the right to reject the caravan under
CRA 2015 for a full refund, no questions asked. See sections 9, 10 and 11 regarding quality and s19 & 20 of CRA 2015 regarding your right to reject.
After the first 30 days, but within 6 months of delivery you need to give the dealer one chance at a repair before rejecting the caravan or demanding a suitable replacement. All repairs need to be done in a reasonable time frame.
The dealer will obviously try and fob you off knowing that you will go to the back of the queue for another caravan if you go down the rejection route and that you want to avoid this route, but you need to stand firmly on your ground. I am one of the people who successfully rejection a caravan from the same manufacturer that was 11 months old. We accepted an inferior caravan and every time we used it something fell apart till eventually we reached the end of our tether!
Just to add we used
Which Legal Services for advice and their advice was spot on allowing us to go up against finance company. Hopefully you will find the links helpful.