I noticed that after eating a few squares of 70% choc my tickly, persistent cough was eased. Thought I was imagining it but just tried again and it worked again - then I found this on the web (BUPA website):
Should I eat chocolate if I have a cough?
According to this study, theobromine, which is a key ingredient found in chocolate, may be effective at stopping persistent coughs.
Hurrah!