That MSUK rule has now I understand been deleted. That was what I was told .by an MSUK steward when I was applying the cross out tapes in the paddock back in 2019.
It vanished from the Blue Book for a while, but now appears to have been re-instated. However, I don't have an up to date copy at present.
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW