[banksider]

Not quite sure what you mean here. Does this help:
I can regain a connection by connecting my win98se desktop directly to the stb. I cannot connect my XP laptops directly because their MAC addresses are different - the router uses the cloned IP of the win98se desktop. (Wonder if there's an issue here??)

But with the router connected to the stb a connection can't be made without the strange cable swopping procedure noted above. I feel there must be a way to do this without unplugging and replugging cables.

This has had me baffled for two or three years now! It's just a drag to have to do this each time the stb locks or crashes. (Which with ntl is not unusual.)