I would post in the request area of the advertising to see what you could get.
I was looking a few days ago and found this one to be the best for the money, at least in my opinion.
IBM X-Series 300/Ensim 3.1
200 GIG TRANSFER
Genuine IBM X-Series Server
Ensim 3.1 Server Unlimited License
512 MB RAM
60 GIG - 7,200 RPM HD
20 GIG - 7200 RPM (For Backups)
Includes 16 IP Addresses
I'm not sure he meant it, but it seemed that he pointed out that he wanted Unix. Webreseller uses Linux, at least for those rather cheap (cost wise) specials. Unix may cost quite a bit more, but you should be able to get it for the $200 you requested, or 300 pounds (someone want to tell me how to do that "l" thing for pounds?).