It all comes down to the description of the goods, the goods have to be as described and any known faults mentioned in the description become part of the contract. There are occasions where other legislation does affect it such a when selling motor vehicles where in the UK any motor vehicle retailed must be in a roadworthy condition.Under CRA 2015 it does NOT matter whether the dealer mentioned the fridge or not.
Can I suggest that you refresh yourself on CRA 2015 particularly S9 & 10 and also 11. See https://www.legislation.gov.uk/ukpga/2015/15/contents/enacted
If the description said the fridge was faulty, and no other agreement had been made to fix it, then the failure of the faulty fridge is part of the contract. The buyer cannot then claim to have the fridge repaired, becasue there was no contract to repair it.
In this case it seems the dealer (or at least someone in the dealer's employ) knew the fridge was faulty before the caravan was handed over. Let's assume the failure to repair it was a genuine oversight, I hope the dealer will take reasonable steps to get it repaired.
But if not the evidence of the check sheet would be enough to invoke the CRA - Unless the dealer was aware of the fault and advised the customer who then agreed to accept the fault without it being fixed. That acceptance would become part of the contract of sale.
If you apply your interpretation of the CRA, then it would be impossible to sell anything that was second hand.