Insurance companies couldn’t give a monkey’s whether you tell them about any mods or not. In fact, they love it when you don’t declare anything, which is exactly the reason you NEED to declare everything. Why? Because insurance Contracts occupy a very strange corner of Contract Law known as ‘Contracts of Utmost Faith’ In this type of contract the insurer doesn’t check any of the details you provide, instead they place the ‘utmost faith’ that what you have told them is true, correct and complete.
‘Utmost Faith’ means the onus is all on you. It’s only once you make a claim that the insurance company starts to check; If they find anything that wasn’t declared that should have been, then the contract (of utmost faith remember) becomes null & void. The insurance company keeps your premium and you get nothing- that’s why they love it if you don’t declare things.
And remember, the bigger the claim, the deeper they’ll dig in order to get themselves out of it. If the claim involves death or injury of a third party, the costs could be astronomical. Insurance company finds something not declared, they’re off the hook, leaving you personally liable to find the money instead.
Hence the old adage ‘if in doubt, declare it’. Sometimes it may add a few pounds to your premium, sometimes not. But at least you can rest safe in the knowledge you’re covered for the worst case, which is exactly when you’ll need it most.