First of all write to the dealer getting proof of posting which is free. Keep the letter brief and to the point with no waffling. Advise the dealer that you have previously contacted them by email or letter and have not had a response. generally sending emails is a waste of time and effort as they don't bother to respond in many cases.
Remind the dealer of their obligations under the Consumer Rights Act 2015 S9 & S10 that the caravan is supposed to be of satisfactory quality. You also have the right to reject under S19 and S20 of the CRA 2015.
Depending when you took delivery within the first 30 days of delivery you can reject the caravan and request a full refund and no excuses from the dealer. After the 30 days and within 6 months of delivery you need to give the dealer ONE chance at a repair before rejecting.
That time period is suspended from the date that you advise the dealer of the faults i.e. if you sent the email within the first 30 days and it is now 2 months since sending the email, the caravan is still within the 30 day rejection period.
If the caravan has some finance on it notify the finance house as soon as possible. If you paid a deposit using a credit card you are also have protection by S75 of the CCA.
Also as advised by the Prof guy "Which Legal Services" are very good and we used them when we rejected a caravan when it was 11 months old! Cost about £9 a month for as much legal information as required.
Consumer Rights Act 2015.