As long as it has a discreet graphics card you should be fine. Though saying that I can play CoH on a Lenovo n500 (everything on minimum settings), that has a Intel 4500 GPU 200Mhz. Won't play WoW though which makes me sad. :'(
My missus used to play on her work laptop a couple of years ago (which was already an old machine when she got it) and as far as I recall it had some crappy Intel graphics card and 256MB of memory. It ran COH, albeit a bit laggy at times. I can't imagine you having many problems running COH on any newish machine. £400 should be plenty especially as newer machines tend to have dual core CPUs and 2GB+ of memory. A quick google gave me system requiremnts for COH as:
Microsoft® Windows® 2000/XP
Intel® Pentium® III 800 Mhz or AMD Athlon 800 Mhz
256 MB RAM
CD-ROM Drive
4 GB Available HDD Space
NVIDIA® GeForce 2 Series, ATI® Radeon® 7500 or Intel® i810G Series Video Card
16-bit Sound Card
56k modem
DirectX® 9.0c
Not much there to worry a modern laptop.
Pyrokine
"Live forever or die tryin'"
That's the old specs. better to look up the Cov specs as they're far more relevant.
From the specs I can see it has intel integrated graphics. not sure on the number but integrated graphics are usually slow and sometimes don't even run the game. ideally you should be looking at some sort of independant graphics card on a laptop, but if your budget is around the £350-£400 mark that the Acer 5735z fits into you're gonna be struggling!
Defiant 50's
Many and varied!
@Miss Chief
My laptop cost ~£350. So it is perfectly possible to get a laptop that runs CoH (currently GR may up the specs 
) for under £400.
OTOH I wouldn't want to run a TF with it... ITF's lag hill would probably kill it. 
Well. After thinking about it, I've canned the laptop idea and decided to go straight for the desktop! Might have to wait for my next wage cheque but it will prolly take them 2 weeks to get my internet connection up anyway.
My MA IDs:
Fiend Space: 211464
Hi.
I'll be moving house shortly and I'm planning to leave my old PC behind as its far to big to take with me, plus its getting a bit old and tired anyway.
My plan is to get a smaller desktop later on, and a cheap n chearful laptop for under £400 at the moment for surfing and older gaming. As I only play stuff like COH, freedom force, bards tale, etc. I'm wondering if I could get away with the Acer 5735z until stargate worlds or thief4 comes out and convinces me to splash out on a dedicated gaming rig.
Any thoughts?
My MA IDs:
Fiend Space: 211464