Stumbled upon this free plugin and it does everything I wanted. No messing, downloaded, uploaded, enabled, works like a dream.
Exactly what I needed, thank you Yuri!
Enabling it needed a quite read of the very clear instructions and once read, it was a doddle to get the sliding thumbnails to appear where I wanted them.
It took me longer to work out how to add a description to the slideshow within my article than it did to install! (Edit the article, not the module).
The one thing I would have liked to find was that it was possible to add the description to the enlarged image, but other than that, this is a perfect Joomla 2.5 extension, thank you!
This mod allows you to set up a module that includes php so I copied and pasted all my existing php year code as well as the text and formatting I wanted from the template and positioned the module exactly where I wanted it.
PHP Year code now displays perfectly within a Module, and it's free. Can't ask for more!