So I've just renewed my insurance (using a broker - H&R), and given what I think is a fair estimate for my mileage. Nothing strange there, exactly what I've always done for my bike and car insurance.

Where I sign at the bottom and send back, they've included a statement that requires me to declare my current mileage and sign separately that it will not go more than my annual estimate over this for the next 12 months. There is also a 'n.b.' which reads "N.B. Should the mileage exceed the agreed limit in this period I understand the insurance will be ineffective."

I've never understood it be an 'agreed limit' before, merely an estimate which, if grossly underestimated, gave the insurance company cause to mitigate any claim I make.

So two questions for any legal bods out there:
Are they allowed to ask me to declare and sign?
Even if I were to sign, would the 'n.b.' statement hold in a court?

And I guess an open question... do most people have this on their insurance?

Any advice appreciated! Cheers