After all my pondering and musings, I have realised that, actually, today should fit into the '2' part of my 5-2 challenge. I didn't carefully cost out the lasagne, only roughly, so can't be as exact as I would like, but I shall say today costs £1.50 which should be close enough to make little difference and may even be over.
So - I have £11-40 as from yesterday morning.
Today's food plans:
B: toast and fruit
L: tomato and lentil soup, bread, home made rhubarb and ginger cake (just a very little bit!)
D: lasagne, salad, garlic bread, stewed rhubarb and custard