The verdict:
Unusual or substituted ingredients:
No unusual ingredients at all - although I've got to say that either Nigella has way overestimated the quantity required for the biscuit base, or underestimated the amount of filling required. If you are going to make these, either halve the amount of the biscuit base, or double the amount of the filling (that's what I'll be doing!) .
Special utensils or cookware: I don't have mini-muffin tins, so I used a cupcake tin, silicone mini-cupcakes and individual tart cases. I spooned the mixture in and pressed it down with the spoon and then my fingers - getting it up the sides was the hardest, but it was ok in the end.
Repeatability: I made these for a playdate with a couple of friends, and I think they were a good choice - can be made the day before, are very easy to transport, no annoying cutting required, just the right size for an after-lunch dessert or with coffee. I would definitely make these again. Just with more of the filling!
Sauciness: These are light and tasty - and would be very easy to modify by adding some berried to the mixture (either before cooking or just on top), or perhaps swirling some melted chocolate through the mix.
Overall pleasure level: Hmmmm, I think these are a 7.5 out of 10 for me. Sweeeeeet!
The verdict: 



While I mostly stuck with the white meringues, inspired by Nigella's description of using the back of a spoon to make "neat nippled small bosomed shapes", I decided to go the whole nine yards and make them pink as well, for added realism (or childish delight, more like!)
Special utensils or cookware: I used the kitchenaid to mix the whites and sugar - meaning this is truly a recipe you can make while doing something else (eg knitting!). Just put the mixer on to beat for about 5-10 minutes and go and multitask! A good way to tell when you've beaten your egg whites and sugar enough is to rub a little between your thumb and forefinger - if it feels gritty, beat some more. You will probably never get it entirely smooth, but the level of grittiness will reduce.
Beat until it is a "gleaming, satiny mass".
Overall pleasure level: I hadn't had a meringue for ages before these - I'd forgotten that lovely chewy centre and crisp crust (heh, bet you can't say "crisp crust" ten times in a row!). These are really very good and fun to make to boot! - 8/10 for me!