Thank you to everyone who commented on my question a few weeks back. I went to the pulmonary department on Friday and although i doubt their enthusiasm somewhat to fixing the problem "Ahh coughs... they keep me in a job on a Friday afternoon" 
They are at least doing something at last! After sharing the information from everyone on here, she has decided to try me with a brown steroid inhaler twice a day and putting me on the waiting list for a CT scan. She said that she isn't promising to cure it, but I reassured her that I am determined to find out what it is, as is having a real impact on my life! Maybe if I keep chipping away at them, I might get somewhere! I am going back in 3 months for a follow up appointment. She thinks I am too young for bronchiectasis, but I reminded her that I had/have UC and she did accept that it is associated with inflammation. So the CT scan should help find out!
The inhaler is aggravating the back of my throat, since it gets quite sore after coughing for so long, but am hoping that it will help in the long run.
I hope that anyone else trying to solve the mystery manages to have success too!
Thanks again!