Not sure. Gone back to 2007 and those below are all I can find ... They cover MkIs and MkIIs. Hope this helps, but if it ain't one of these, best p-m David direct, as been right through his archive file and deleted file, and these are all I could find . Atb: G.
http://www.airgunbbs.com/forums/showthread.php?t=358745
http://www.airgunbbs.com/forums/showthread.php?t=332671
http://www.airgunbbs.com/forums/showthread.php?t=254453
http://www.airgunbbs.com/forums/showthread.php?t=254613
http://www.airgunbbs.com/forums/showthread.php?t=189988
.