Today I solved the problem with the plugins page. I revisited Jay Allen's post regarding FastCGI and read everything again, and tried this:
And it worked. I was able to move off the plugins page. I'm stumbling around when it comes to using the shell, I'm so used to using FTP or the cPanel my old hosts provided. It's a similar result to over-writing the mt.fcgi script but way easier and quicker, and probably better all round. I can see I need a few lessons on the use of the shell.
At present I'm using Window's HyperTerminal, just Telnet (I think), and I haven't set up my cron jobs yet because I'm unsure how to do it. If I learn something new every day, I'll get there eventually.
I guess it would be safe now to upgrade again to the latest 3.34 version of MT. I wished I'd tried this step two days ago when I was having all sorts of problems and didn't know what was going on.
Everything seems to work fine, though there's a bunch of lines in the error log, but I guess they're safe to ignore.
I have less than a year now to give up smoking, I promised the kids I'd give up before I turn 50. The count-down has begun.