Finally in 4.2.0.2673 the mach team has found the wxAuiNotebook Class to make the tabs look pretty, I had already coded them into my screen, and the old mach wxnotebook tabs looked dull against them as in first pic, but now look a lot better. (second pic)
But unfortunately mach4 now starts off on the wrong screen and so have I to put scr.SetProperty('Screens', 'Current Tab', '0') in the Screen Load Script.
DazTheGas