I'm a very happy camper.
Today, after almost 18 months, I finally got some good news, my ex and me are no longer connected via our property, the Land Registry have eventually confirmed that my application to sever the joint tenancy has been served. I can breathe a sigh of relief and now I know, that if anything happens to me, she cannot automatically claim my share.
My will now has all my instructions laid out in it.
Happy, happy and happy.