Ian - yes - 24L/06R will close between 12 and 3pm.
I have just checked and the forecast is decent for tomorrow. But they have already switched to 06L for departures, and I believe the forecast is for the wind from the north, so I reckon it is a high likelihood that your plane will depart from 06L, Noel.
For anyone who is there who wants to help Noel out, I would suggest a walk up from the 24L threshold (mounds) towards a position opposite the ATC Tower, so that you can get a shot like this:
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Photo © Paul Markman
I have a few shots of Singapore departures from 06L from this spot, and they all appear to rotate from a similar kind of position - I would say midway between opposite the mound and this position opposite the Tower, close to Moss Lane.
Childcare permitting (which I think it won't) I may try to nip down. I hope this helps.
P.S. Colin - my Met Office forecast has Tuesday as cloudy, but not rainy! If that is so one consolation might be that your shots aren't heat hazed to b***ery. If the sun is out this weekend, and it is getting warm now, and the wind is from the north, that smacks of a significant temperature differential - perfect conditions for the dreaded heat haze.
[Edited 2006-04-28 18:05:43]