A quick scan through some of those links seems to indicate that Harris Gun works has changed hands and names and been in some trouble.

eg: http://yarchive.net/gun/politics/mcmillan_family.html

Scoll down and read the second email. It looks like if it is a pre-late 1991 action it is a better one than what may have been produced later.

If the rifle was built by Smithson and you believe what you hear about him (I've only heard the positive promo on the 'Death By ...' DVD's) then I doubt he would have used a dodgey action, if the promo was correct.

I am not familiar with the rifles at all.