I just tried out Sheldon's tool (if you'll pardon the expression!) and it worked a charm. The fixed cup is now off the bike for the first time since 1982. This brings me to my next problem - what should I replace it with? The last time I cleaned out and reinstalled a bottom bracket spindle would have been about 1985. Things have moved on of course and it seems that a sealed cartridge is the way to go. Am I right in this assumption, and if so, is there anything else I should consider bearing in mind the age of the frame?

Thanks.