I was very surprised at the optician today to have been addressed as Mrs, as it's a title I've never used. I did correct them, but I don't think they corrected it on my forms. I have to go back soon, and didn't have the energy to argue the point.
The odd thing was that the optician introduced himself as Jeremy rather than Mr Smith (actually, I've no idea what his surname is, as it turns out.)
I'd rather not use any title, but if I must, as many online forms insist, I prefer to be Ms, or Miss at a pinch. Not Mrs. That's my mother.