Jim:
Many thanks on the leads. I found an exploded view of the 123 via packstoves.com (you were right about the site..) and was pleased to find I appear to have all the parts. Also banged about a bit on YouTube (should have done that last night... D'oh!), and found out my stove was too old to have the cleaning needle affair (which is what I thought I was missing... D'oh!x2)
Still missing the cup/"saucepan", handle, and brass windscreen/stand.
Will finish cleaning it tonight and will try to fire it up tomorrow after work. Been 25 years since it had a workout.
.....CLIFF
(like, who else?)