Hiya looking for some help please :)! I am looking to hire a classic car for...

Hiya looking for some help please :)! I am looking to hire a classic car for my wedding but the car excess is £2500 should anything to happen (which obviously hopefully it won’t but as you can imagine is a big risk!). From other car hires I have done you can normally pay an additional insurance company to insure against the car hire excess but from a few of the companies I have looked at online they limit the value of the car and the age of the car to under 10 years only. As this is a classic car there I can’t use these companies. Does anyone know of any specialist insurance companies that offer this? Thanks in advance! Xxx