I might have worked this out.
The pilot jet that is in my attached pic is not adjustable. My mistake. It should be screwed right up and home, and the pilot jet retaining nut screwed tight onto it so it all stays put. If that jet was loose, that might have been causing my rev holding issue. So the petrol drip tray position doesn’t matter, because I don’t need access to the jet to adjust it... the jet just has to be screwed right up and tight and the retaining nut and fibre washer lock it in place.