Hello bigfoot,
Very sorry to read of your incident and the CC's. attitude to your claim.
Cearly I do not have access to all the incident reports and statemsnts, nor do I have CC insurance so I cant check policy details my self, but I am left wondering about the your situation.
Let us take the factual aspect first of all, My sources do not include the Xtrail 2.2dCi data so i will assume it is similar to the 2.2TDi, which has a quoted KW of 1520 and max tow of 2000Kg. The only Challenger 540 seems to be a 2007 model with an MTPLM of 1480.
Based on those figures the ratio comes out at 97%. However the caravan is well within the cars legal max towing weight.
The other point about snaking is a bit more tricky. You said the outfit sufferd a blow out which I assume then caused the outfit to become uncontrollable. If this is the case than I do not think the CC can resist the claim.
But it seems the CC may be saying that because the outfit snaked it places extra load on the tyres and cause a blow out. The point being that you should not allow it to snake in the first place! They are possibly also implying that because of the poor tow ratio, the outfit is more likely to snake. The truth willbe difficult to prove unless the Police or traffic agency took measurements and position's of skid marks on the road, which can be interpreted
If the CC are placing a limit on their liability determined by a particular ratio which is less than the legal limit, they MUST tell you about it before you take out the insurance, or renew it. They should also ask as part of the proposal for details of the outfit. They cannot retrospectively impose it such a fundamental variation to what is a legal limit. Equally and assuming you told the CC about your outfit, if it fell outside the ratio they permit, why did they accept your proposal when they had no intenti of providing cover? That would be miss selling and is clear breach of the Trades Descriptions Act and the Financial Services Regulations.
I am not a legal expert, and the above is just my opinion on the information you have supplied. I suggest you write to the company along the lines I have outlined and ask the to reconsider the claim, or ask them on what basis as defined in their policy details, they are declining. I also strongly suggest you seek professional legal advice to pursue the issue beyond that.
Dont be put off by the fact that insurance companies are supposed to know what they are doing, I have heard of several cases where drivers have had their claims upheld where the insurers had previously declined.