AIBU to be fuming?!
She refuses to cover him up and isn't applying any sun lotion. Baby is 10 months.
Apparently no one puts sun lotion on their kid's in her country, and they're just kept out of the sun when it's at its strongest (between 1.30/3) 
She's adamant he doesn't burn, and she doesn't. Which is true. But burning isn't the only sign of skin damage by the sun. So is a sun tan. Any change to pigmentation is, isn't it?
I was at the park with her and all the kids yesterday, I made a point of putting sun lotion on all of mine, and made sure I had loads in my hands when I said "Oh I've loads left. Let me do yours. Might as well, loads left
"
She was very
and said I'd rather you didn't. I didn't know what to say to that. 5 minutes later she claimed to have a migraine coming on and left.
I've been advised to report her to her health visitor but I know she doesn't have one.