Oh dear, I don't think we should start talking about Royal Oilfields. If yours got hot and bothered riding in a bit of mud on a winters day in England you'll understand how quickly they wilted in an Australian summer just with normal use. That floating bush big end and having the oil tank integral with the crankcase to ensure nothing cooled down was not a good idea. Such a pity as they looked good and were early adopters of comfy swing arm rear suspension. Of course the excellent suspension just guaranteed the engine failed even more quickly as normal touring speeds could be kept up over country roads that slowed everything else down and gave the engine a breather. (Dowty forks, rigid frame, anyone?)
Sorry, got off the point there a bit but the Royal Enfield myth makes me roll my eyes on occasion.
Back to the subject. I think you've both confirmed that UK observed trials practice has little practical value for road use in hot climates.
Cheers,