AJAX - Welcome to my CV
Finally found a genuine / commercial excuse to do something legitimate with AJAX. I decided to use the Prototype library, despite the fact that it's not well documented by the guy that developed it, there is a plenty of nifty pieces of documentation out there for it.
In the end, this kind of stuff was very easy - I suspect though that polishing what I've done and making it a nicely integrated 'widget-type-thing' that a visitor/customer to the website will use is a whole nother thing.
I'll keep you posted.