Hi mem,
As we'd say in Australia - you beauty, all sorted! 
I've read so many threads where you've helped others, on matters MUCH more complicated than mine. It's a rare thing for someone to be able to provide assistance so happily and helpfully to beginners and 'experts' alike; your parents would be proud! 
Thanks for your help, and I'm sure I'll have more questions as my project matures. FYI, the project goes something like this:
- A remote automated camera system to take photos of key wetlands once or twice a day
- Using a Canon Powershot A720 consumer camera, with modified firmware (see CHDK Wiki | Fandom for more info - I'm sure there are people here who would be interested in what the CHDK community has achieved)
- Thermistor to monitor enclosure temperature, and operate fans when required
- DS1307 mini-board (DS1307 Real Time Clock Mini Board) for RTC
- Arduino to control fans, camera power & solenoid to turn camera on at specific times
Believe it or not, this is all part of a WORK project, so I get to spend my time playing with Arduino & all sorts of other fun bits & pieces; I'm LIVING the tinkering philosophy!
Thanks again for your help, that sketch has compiled happily under 0012. Tomorrow I'll start working on how to integrate this with the rest of the code I've pulled together - hopefully my DS1307 board isn't far away!