Good question, it's one of those gospel points that when you look it up you can't find. I've just checked the standard wording on a permit, and the standard conditions of an NPPL(M) and neither contain that restriction. Looking at article 9a of the ANO, which contains the basic permit restrictions again there is no such limitation.
It is listed in Brian Cosgrove's Microlight pilots' Handbook but without a document reference.
The ANO does list "not out of sight of surface" under privileges of an NPPL(M), which as you rightly say doesn't apply to the holder of an IR or IMC - so you may well be right, but I think I need to consult an expert.
G
Last edited by Genghis the Engineer; 3rd Nov 2004 at 20:01.