Thanks for the valuable advice.

I'm in the process of dealing with her as we speak.

I do prefer to deal with it as amicably as possible and she has apologised profusely.... so I'm open to giving her one final chance, even though she is a tad of a pain in the you know where. 

This time and this time ONLY though - I will stand my ground!

Thanks to you and all that have replied.  🙂