I posted my first 'Ponder' post in Feed Yourself for a Pound a Day (the Facebook group) this morning and got some fantastically helpful responses.
The one that attracts me the most is the 5-2 suggestion: £1.00 a day for weekdays and £1.50 at the weekend. That way I can continue with my frugal ways and yet use up some of the freezer resources on two days a week. Given that I am off challenge more or less every other weekend anyway, it won't make a huge difference really.
I haven't made a final decision and will still think about it, but that's what appeals right now.