Typically Insurance policies have an excess on them although something like a Critical Illness Insurance plan will not. This is where you pay the first amount towards a claim. Generally on something like pet insurance the excess will be lower than if you were claiming on a horse insurance policy.
Sometimes a company may put a percentage onto the excess which generally means that there is a minimum claim amount for example £175 or 17.5 percent which ever is greater.
You can not claim if your excess is lower than the minimum of £175. For example if your claim was for £2400 and your minimum excess was as mentioned as above that you will have to pay the first £420 towards the claim. The rest of the claim will be paid out by the insurance provider. When making a claim for animal insurance you can stipulate whether you pay the full amount to the vet and claim it back off the insurance company or you can pay your excess and let the insurance company pay the vet.