Hmmm.... well I would not recommend a Celeron @ 1 Ghz at all. Also it seems very bad value for money at 159 UKP!!!
I'm almost glad you have said this - I have never had a high opinion of these Celeron processors either, and as you say, it's quite a lot of money for what it is.
This Gigabyte ATOM board looks to almost fit your spec; http://www.gigabyte.com.tw/Products/Motherboard/Products_Spec.aspx?ClassValue=Motherboard&ProductID=2850&ProductName=GA-GC230D(Atom)
But you'd have to remove the small processor fan and replace it with a heat-pipe cooler
Whilst I appreciate the suggestion, this doesn't really fulfil my requirements - namely the lack of gigabit ethernet and required video outputs (ideally I would like something that will work with both my ancient PAL TVs, either S-video or composite, and also be ready to use with a flat screen for when I eventually invest in one, either DVI or component).
However, I am really quite interested in what you have said about replacing the fan with a heat-pipe cooler, as this suddenly makes a huge number of other motherboards available to me. Could you do this with ANY mini-ITX motherboard, or do you just happen to know that it is possible with this particular one? Could anybody possibly recommend a site that I could start looking at for these heat-pipe coolers please? The only ones that I can find either have a fan attached to them, or are intended for the northbridge. Do they use a standard fitting?