Idun - obviously a sensitive topic.
Personally I don't think any of us from the UK, arriving in middle age or later, can ever be as fluent as native born.
One advantage you and I have, Idun, is that we have the NE England broad vowels, more easily understood by french people.
My friend in France came from Devon and the locals couldn't understand a word . Though she gets away with it because she's such a cheerful sociable person. They're still there, after 30 years.