http://a.img-dpreview.com/reviews/Olymp ... -side2.jpg
I have now (so far) cured this. I searched through a pack of mixed neoprene O-rings and washers, purchased for domestic plumbing repairs. I found the perfect O-ring for this application. It is 20mm diameter and about 1mm thick. I simply super-glued this to form an outer ring around the Main Dial. My thumb can no longer press any of the controls when flat across, as in shooting position, but the central button is readily accessible to my thumb and the others to thumb tip and finger tips.
I got my wife to photograph the modified camera with her point-and-shoot camera. I have done what I can with the image but it shows the ring. (Some spots of white are from the superglue and indivcate the inner and outer limits of the O-ring).

I'm sure this can work for other camera models.
One concern remains: How will I ever afford my next camera, now that the rapid accumulation of cash in the 'swear box' has come to a halt!

Harold