Being referred to as Mother in Law's Daughter

Socialise and chat about other areas of your life
I am probably being a bit pedantic in the greater scheme of things, but I am seeing more and more care plans, GP notes, case Co reviews etc, where I am being put down as main contact (fine with this) but then shown as my Mother in Law's Daughter! Much as I love her and would do anything for her .. clearing up vomit at 2am and washing infinite amounts of piddly bedding, to name but a few, I am not a blood relation. I have been with her youngest son for over 25 years now, married for 20 but when people read this, I think it gives the wrong impression of my relationship (and therefore responsibility) to her. Hubby says I am too sensitive and should just ignore it as I already do enough to support her, but I do resent being referred to as her daughter, particularly as my own mum has already passed.

I have a case review with her Social Worker later this week, and am going to stress the point, but Mum will be there and don't really want to upset her as she always says to everyone "You are like the daughter I never had".

Am I making a mountain out of this?
Not at all! I have just been saying to eldest son that I like to be referred to in all documents by my four letter shortened version of my Christian name. I say this at the beginning of every meeting with Social Services, it's never minuted, and throughout the minutes it refers to all paid staff by their Christian names, and I'm Mrs.xxx