Dear [name of insurance company]
[Ref: policy number]
On [date] I submitted a claim on this policy for [describe damage], which occurred on [date].
Although you have written to me on [number of times] occasions denying liability unless I can provide [evidence requested], I feel that I have presented sufficient evidence to you in the form of [describe] to prove my claim is covered by the policy.
I refer you to the Consumer Protection from Unfair Trading Regulations 2008, in which it is considered in all circumstances to be an unfair commercial practice if an insurance company continues to require a consumer who wishes to claim on an insurance policy to produce documents which could not reasonably be considered relevant as to whether the claim was valid.
It is now […. Weeks/months] since my claim was submitted, and I feel that you have taken far too long to deal with this matter and that I have already presented sufficient evidence in support of my claim.
Unless I receive your proposals for settlement within 14 days, I shall put the matter in the hands of the Financial Ombudsman Service.