Oddly enough, I have one of those modified rockerboxes on this A7. Somebody has neatly machined and threaded a hole in the centre of the box, which takes what looks like an oil tank cap ( or a chaincase inspection cap if you prefer ). Certainly very handy for shining a torch through to locate that last pushrod that just won't line up !
Trev, even though I must have done it a couple of dozen times, I still haven't mastered it. It either goes straight on in five minutes, or it takes an hour, which is why I grabbed the modified box on Fleabay a year or so ago. Sure makes life easier for me, and I have more " five minute " jobs than one hour ones these days.
Norman