>>I agree with you naomi.
>>
>>Best broken down into sensible pieces.
>>
>>It looks like something thats had a lot bolted onto it over a long period.
>
>Hi Nicholas, I think that's exactly what has happened - I have just inherited it :-( - how could I break it down into smaller pieces ?

Nick is on the right track. This inherited code is hard to understand. Break it down to its core, prove that works, then add pieces back until it breaks.

Debugging can be drudgery. Scut work. It's rebuilding a wall brick by brick. Oddly enough, it's about my favorite part of software development. When you finally nail that b****d it's a great feeling. I have been known to do the Snoopy dance myself ;-)