My apologies, Paul. I just provided individual stages of my project, because I considered each stage a separate thread - I never stopped to think they'd be interconnected - and also that if I detailed my project requirements in full, it would be an extremely long thread and too much to expect anyone to read, let alone suggest any code.

Thanks for the further links. I'm going to work with the codes you've provided so far, and see what needs further refining. Then I will produce a full project proposal. I appreciate your help so far, and I don't want to push my luck asking for more code for free, so I'll put my project up for bid when done.