Thanks, for your reply. Medication; which to me is innocuous and with previous insurance broker was acceptable, but because this is a standard (cheap) policy offered to airlines the policy has some very specific limitations.
I did telephone the insurer but they would not amend the cover even for an additional cost, which on reflection I do understand for the reasons above. They simply suggested that I should buy an additional policy (from another company!!) but that in the event of a claim that I would only be permitted to claim from one policy, which is fair enough. However there is a lesson for others who like me don't fall within the standard deviation; speak to someone before you commit to buy, or read the conditions within 10 days otherwise you may not be covered and you will loose your money.
The insurer gave the following scenario: "for example if you were to stumble and fall and needed treatment and if our Doctors when looking at your medical history concluded that your medication was contributory then we would not cover you, you would be liable for all expenses relating to the injury...., therefore it would be up to you to challenge the Doctors assessment that the medication didn't cause the injury either directly or indirectly". All medication has the caveat of do not drive, operate machinery etc!
If only the high street broker whom I've dealt with hadn't retired! I'm now in this minefield and not sure who to go to!