Thanks Amos for the potted history - that's just the toe-hold I needed.
I hadn't realised just how much Mac music software there is/was around. Following are some links which give a lot of information. The first link, while not terribly current, has some good stuff in it. There are a number of sites where you can download software
http://www.lancs.ac.uk/users/music/research/sware.html Lots of Mac software
http://ace.acadiau.ca/score/others.htm A mixed bag at an untidy page
http://www.sincrosoft.com/data/sez8.asp?Language=eng Amadeus Opus Lite
I hope that some gems are lurking there somewhere. Regards, John