I cooked this dessert for my mum's birthday last night. It didn't come out quite as expected. In the name of preventing similar mishaps for future readers, I present these addenda to the above recipe.

The oven settings above aren't too helpful if you have a gas oven. If you do, you'll want to pre-heat it to Gas Mark 2, then reduce it to Mark 1 as soon as the pavlova goes into the oven.

If by some chance your egg mixture isn't even getting vague indentations in it, let alone 'stiff peaks', the easiest thing to do is simply beat in more sugar, whisk it for a while, test, and repeat until you could reliably turn the mixture out onto the baking sheet without it oozing over the edges and covering the sheet in a thin layer of runny foamy stuff.

Update, a short while later - the estimable sneff messaged me to say:

It is very important in meringues to get the white to the right consistency - i.e soft peaks, before you add any sugar.
True - you can continue beating the white with the sugar, but any additives will seriously affect the whites ability to form a protein structure. The moral is - always wait to the right moment before adding sugar!

Delia Smith's pavlova recipe gives a few helpful hints and tips, including one I should probably have paid attention to:

We have had some worrying reports of under-cooking at gas mark 1. Our investigations suggest that in some ovens – modern ovens, particularly – gas mark 1 is not what it used to be, ie, 275°F (140°C). Before you start a recipe requiring gas mark 1, please buy an oven thermometer and check the temperature your oven gives on gas mark 1. If you find that your gas mark 1 setting is a bit too cool, move the dial halfway to gas mark 2 and test the oven again. If the oven is too hot, adjust the dial a couple of degrees in the other (cooler) direction.

I cooked my pavlova for an hour (on the advice of another random pavlova recipe somewhere on the net) and left it to stand for half an hour, which turned out to be nowhere near enough - the pav was more like white, vaguely eggy mousse inside rather than the nice brown crispy meringue it was meant to be. I put it in the oven for another half an hour (again on Mark 1) and proceeded to forget about it. In the morning (after Mum having come down in the middle of the night and turned it off) it was utterly perfectly cooked.

Delia's advice is to:

...turn the heat right off but leave the Pavlova inside the oven until it's completely cold. I always find it's best to make a Pavlova in the evening and leave it in the turned-off oven overnight to dry out. It's my belief that the secret of successful meringues of any sort is to let them dry out completely, which is what this method does perfectly.

I found the leaving-in-the-oven-overnight method to be extremely successful: I just had a bowlful of the now-properly-cooked pavlova and am happy to report that it was absolutely delicious.

I altered the recipe a bit for randomness's sake, and used a small amount of greek yogurt with honey and caster sugar instead of the cream, and a sauce of raspberries blended with sugar instead of the fruit.

www.deliaonline.com/recipes/r_0000001219.asp - Delia's Pavlova recipe
http://www.deliaonline.com/cookeryschool/a_0000000715.asp - advice on cooking on Gas Mark 1