If you have purchased the motorhome through a finance agreement, contact the finance company and tell them you are rejecting the vehicle...they actually own it until you complete all payments, so it becomes their problem. Invariably things happen when Finance Company's get involved and should sought it out.
If you have no finance agreement in place, then under the Consumer Act, Assuming the manufacturers letter is genuine, you have to give the dealer the opportunity to make good repairs/faults . If they take it in and fail to not sort them all out in one go and in a reasonable timescale, then you are legally entitled to Reject the vehicle and recover your costs. You should write to the Dealer and give 14 days notice of Intention to Reject. If nothing resolved, after 14 days, confirm in writing you are rejecting it and tell them to pick up the vehicle. They have to refund your purchase costs - in theory they can make a reduction for use, but unlikely. If they fail to respond, them the law is on your side.. I would also recommend involving the Manufacturer - so write to Burstner UK and also advise you will pursue through the Courts under the consumer Act. They may say your contract is with the dealer and not their problem but ignore that and push back.
Good luck
If you have no finance agreement in place, then under the Consumer Act, Assuming the manufacturers letter is genuine, you have to give the dealer the opportunity to make good repairs/faults . If they take it in and fail to not sort them all out in one go and in a reasonable timescale, then you are legally entitled to Reject the vehicle and recover your costs. You should write to the Dealer and give 14 days notice of Intention to Reject. If nothing resolved, after 14 days, confirm in writing you are rejecting it and tell them to pick up the vehicle. They have to refund your purchase costs - in theory they can make a reduction for use, but unlikely. If they fail to respond, them the law is on your side.. I would also recommend involving the Manufacturer - so write to Burstner UK and also advise you will pursue through the Courts under the consumer Act. They may say your contract is with the dealer and not their problem but ignore that and push back.
Good luck