Gee in response to your question about not having witnesses, in my experience, most types of unacceptable bahaviour goes on when there is nobody around  but this should not stop you diarising when things happen so if you do decide to take things to HR, you have a detailed log of events.

But before you go down this road, I believe it is a good idea to speak to the person concerned as they may not realise the effect their behaviour is having on you.

Hoping things are improving for you Dippa.