HR impartial? That's SOOO funny...in an unfunny kind of way. I was unfairly dismissed from my job whilst undergoing fertility treatment after 3 miscarriages. It wasn't related to this, directly, but my boss started bullying me after she found out I was undergoing treatment. Coincidence? I think not!
I was advised by a snarling, nasty HR manager, in the middle of a grievance I'd raised about my bullying manager, that I had no job (since my lm had taken it away from me several weeks before...the straw that broke the camel's back) and so, was effectively redundant.
I disliked my manager (she was the named party in 4 unfair dismissal cases that year) but I kind of felt sorry for her as well. She had a breakdown a few months after I left...tried to top herself. She landed in clover though, getting a job that paid uber money in Europe. I still feel sorry for her...she'll never be happy as she was bullied when she was young and will always be a bully herself.
Back to the HR manager, I think he's the devil incarnate. His responsibility is supposed to be to ALL of his employees, but he was just a backstabbing, barking, bar steward. But I'm not bitter (much!).
I didn't get legal advice (which I vageuly regretted) but I took the Industrial Tribunal route (on advice from an independent HR manager from another part of the company) and got a settlement. It wasn't much money, but it covered my stay at home expenses when our daughter finally arrived!
Good luck with it all hun...and though you may feel like crap now, with everyone denying what happened, you know you're right. And the fact that you're strong enough to do something about it says something fab about you.