Thanks, nutsforsmiths, that's good advice. I made a tool out of an old toothbrush handle dremeled a little bit, to push in on the magazine catch. On most pistols it's fitted a little tightly and needs some urging to move. I was tired to scratching it with pin punches, etc.
If you take parts off the lockwork assembly, note carefully when you remove that little "C" shaped piece at the front of the mainspring. It has to be replaced exactly the way it came off. It's possible to put it in backwards; if you reassemble the pistol like that, it won't shoot and you can;t disassemble it. Major surgery to put that right.