I have had a horrible cough that has led to a pulled muscle or something so when I cough, I want to cry from the pain. My dr recommended guava syrup, which I have to say - despite my reservations, is working.
I am not in England, but I am sure you can get it at health food stores. I highly recommend it for anyone suffering from a cough, it has been really frustrating not being able to take anything, but this works!
Just wanted to share.