Hmm that's quite a good idea you have there W~M!
I'm the same as you Suzi-q, lost quite a bit of weight before the summer, but with the holidays and not working (physical job, term time only) I have piled it back on a bit. I know when I start back at work (next week) I will lose a bit of weight but have to try really hard to get anywhere other than that. I do that Charlie Brooks DVD and it really has helped me but if I miss doing it one day I find it really hard to get back into the swing of it again, hence why I have only done it once this summer!
I'm ok because I know next week I will start to get some sort of motivation again, but for you I would maybe keeping changing what you are doing, say one week do a DVD, the next week do a lot of walking. Try to plan your meals too so your not just grabbing whatever there is. Also I have been told if you have mini snacks through out the day, it keeps your metabolism going and you burn more fat and calories.
Good Luck!!