Brian the reason you have to drill the nuts is section Q 19.7.2 blah blah blah.... And in thread contact Over a min. Length of 1.5 bolt /stud diameter length....blah blah blah. So you drill your nuts so they can check you have inserted the thread Far enough into the nut. I think I got picked up once on this but I decided to leave my nuts as they are.
Thanks for this, I knew there was a reference to the stud size somewhere though unlike you I had failed to find it. Clearly this is what had so exercised the mind of my original scrutineer but his insistence on my drilling the nuts was wrong it would seem; as Onno says you can always undo the nuts to check the thread length.
Brian
... alternatively do as the Regulation says and fit centre-lock type .... like some have ..
We call that safety reasons and weight saving. And it takes some stress away in case of a tyre change in the heat of the moment. I loved the centre nuts on the FF2000 for that reasons.