No worries Triskeliongirl, after reading the advice above I don't intend to add to what I'm eating. You're right about the numbers, the average of the yellow bars over the month (mean or median) was around 1700 calories/day. When I added in my exercise estimates, which I appreciate are approximate, the average dropped to around 1200. Whether that's the right value for weight loss seems to be personal. As I'm on the heavier side, don't feel lethargic and have the energy to train effectively, I agree with you it's likely that it's not too low (as per my original question), and from the posts above should a reasonable starting point. The big things I think will be keeping things going for a longer time, and keeping my net calories steadier in order to try and boost my metabolism rather than having it stop/start...

Thanks all, woohoo