Thanks for looking this further.
I only got as far as the colour being returned from the border@ellipse function was different between the windows and android version (probably due to my device only having 16 bit graphics). Windows returned FF000014 (when setting the colour to 20), but my device returned FF000010 instead. But setting the colour to 16 in the SetRenderDrawColor line still didn't work properly.
Anyway, I have just installed version 1.00b and it is a lot better in that the ellipses are now being filled but I am still getting a flashing screen background.
I will continue to investigate and report back.