Our friend Simon Cotter in Australia seems to have sorted out the puncture problem. He told me, "I used a chemical that you add to the air in the tyre which stops leaks. It works a treat. However if you use tubless tyres the stuff reacts to the tyre itself and causes huge blisters! So the bike shop fitted tubes and the chemical and hey presto! no more punctures!"
Whatever it is, it's available here too so perhaps we ought to enquire about that, just a thought.
Thanks, Simon, for the pointer on that one.