Re: Not great news for youngsters
Wel, that's the civil service for you. I was in the opposite situation, a Brit settled in France for many years but with no interest in becoming a French citizen (friends who went that route reported it as being horribly slow and complex, with dossiers timing out even before they'd been reviewed).
To my great surprise my residence card was transferred into the settled version in a couple of months via one online application. The issue of proof is a little easier because the French are happy to carry identity papers, something that the British would not tolerate.