jefmcg
Guru
Let us know how you get on.I think that's what it could be and thanks everyone for your input. Am making apt later today.
My thought would be (assuming the doctor doesn't want to send you off for cardio tests immediately) that you should get some Salbutamol/Ventolin and use it before the next ride. If the symptoms abate, then it's time to launch an asthma management program with your GP. If they don't, then back to the GP for further, more invasive investigation.
My mild asthma is kicked into touch by a few doses of ventolin. Other people need daily inhaled steroids. More serious cases need ... I don't know. Hopefully you don't find out either.
good luck!