Thanks for all the advice so far folks,
My medical is not until June, so I have a little time to play with. I certainly won't be telling any untruths to my AME, as I have not formally been diagnosed with asthma, I just find myself susceptible to bronchitis, changes of air temperature and coughing fits after a bout of laughter. At the moment, I'm more P1ssed off with the fact that after 10 days and a weeks worth of oral steroids (amongst other stuff), I still have the cough and it's worse than ever.
So far I have managed to pull a muscle in my neck through coughing and a couple of the bouts cause headaches at the back of my head with each couch. The headache is quite possibly due to the severity of the cough. Mind you, I had a mild pain behind my left eye after a coughing fit yesterday, which was very disconcerting. There was no associated vision problem, just the pain, which thankfully eased after 5 minutes or so.
Off to see the GP tomorrow, but why oh why can't I get rid of this thing? There's not even any phlegm to make it feel as if the cough is there for a reason.
Obs cop