Thank you MichaelH. My name is also MichaelH(irsh) so replying to you is rather strange!
Your addition of Emmanuel Gorjeon's EG Series (I wonder how he dreamt up that plugin's name?) is a really gratifying discovery for me.
Just after writing that comment to rughooker, I loaded up Darren Ethier's 'Organize Series' plug in and got Fatal Errors, no matter how many other plugins I disabled.
I then turned to install Justin Tadlock's 'Series' plugin.
I don't know whether it's just me being thick, or whether anyone else finds his installation and use instructions are a bit vague and generalised, but after reading the readme file several times, I still had little idea of how to deploy the plugin, step by step.
I was reluctant to pay to join his support forum until I knew how the plugin behaved, and whether it was right for my blog.
If I were to have a problem with the plugin, then I think it fair enough to pay for support, but I didn't feel it was right to pay for an accurate how-to of the functioning of 'Series'. Sorry, Justin
Which is why it's good to discover EG-Series; It seems to tick all the boxes, at least on first sight. I'll give it a whirl and report back if it's successful.