Is this a lease as a company car or a pcp type lease where you are liable for the excess mileage?
If it is the latter, the excess mielage charge will be listed in the contract normally a few pence per mile...
So if, you.re 2K over and the excess mileage rate is, for example, 10p per mile your cost is £200...
It isn't too bad, depending on the excess mileage rate...