However, asking for info re. procedures on sites like this has its risks
So true...... especially as you have quoted...
c) while descending between FL 410 and FL 280, maintain a track that is midway between and parallel with the organized tracks; and
Unfortunately I can't find find a reference to that procedure in the
GUIDANCE CONCERNING AIR NAVIGATION IN AND ABOVE THE NORTH ATLANTIC MNPS AIRSPACE Edition 2010 and this is dated later than your reference....
NAT Regional Supplementary Procedures (SUPPS) (Doc 7030) Working Copy – 5th Edition - 2008
So which are we supposed to follow?
Mutt