Tanser honey sorry to hear that you are going through this. Bullying in the worklplace is just awful and you do right not to tolerate it any longer.
From this moment on you need to keep a written account of everything that is said and done to you. Including who said it, who was there, most importantly how it made you feel. Report every single instance after you have sent your letter and make sure you get a response from the person you make the report to.
You can also contact these for some really good advice and support about bullying in the workplace
http://www.bullyingbusiness.co.uk/html/employees.html
Hope this matter is resolved soon, there is nothing worse than coming home from work upset and frustrated when you feel things are out of control.