Cheers for the help so far all. Think I might have sussed out the problem..

I noticed that my N800 could only see the network shares when my WinXP games machine was on; not only that, but it could only see the shares that the games machine could see.

I looks like the games machine is acting as a temporary WINS server when I click on browse networks in Windows networking and the N800 is getting the network shares directly from there.

Getting stable networking SHOULD be as easy as setting eiither my Linux server or one of the other computers on my network as a full WINS server.

Any body else done this on their own network yet, and has it worked?