There are a few brokers who offer assurance for older cars (>30yrs).
Does anyone have any experience of any of these, please? I cannot make out the company Clavel (assurancesclavel point com). They have given me a price (super low) but one of their first questions asks whether I have another ‘normal’ - i.e. not historic - car insured with another company.
I have gathered from somewhere that they somehow ‘piggyback’ onto the driver’s main insurance. Is that a possibility?
Is that they want to ensure the classic car is not their daily driver.
No idea about piggy-back… but it’s standard procedure as far as I know… we have to assure the classic company that we do have a Main Car insurance…
I’m sure @fabien will have a response to this question (he may even be ab;e to offer a policy) 
Correct 
Not only a possibility it’s mandatory. All French insurers will require proof of main vehicle insurance (non historic) to be able to insure your historic car
Thank you all, I now understand.