It's not JUST Groupama - Swiftcover don't either.
I found out this to my cost last year after I got taken out in my last but one ZR TD by an idiot in a Focut ST170. I got another ZD and transferred the insurance to that, but when it came to light that the original car had previously been Cat C'd, they retrospectively cancelled my insurance (even though I was now driving something completely legit), saying they should never have insured me in the first place. They also charged me a cancellation fee.
Then the new place that I insured with, who just happened to be the other driver's insurers, also charged me more for having been recently involved in an accident - even though THEY admitted liability!!! Watch out that your new insurers don't do the same to you - try a few "what if" scenarios when getting quotes, make a full disclosure then argue the toss.
Licensed fraudsters. Makes me mad.