Thanks for your reply. I was really asking which of the
files were actually required, and what needed to be in them.
I already had the details of hostname, IP address etc..
Anyway, I carefully edited the network.opts. I think the settings weren't the problem afterall!!
After reboot, the network was taking a couple of minutes to come up. Ping initially hangs and gives "Destination Host Unreachable" before coming to life. I wasn't being patient enough, and assumed it just wasn't working.
/var/log/messages has the following
kernal: eth0: transmit timed out, tx_status 00 status e000 kernal: eth0: Tx Ring full, refused to send buffer
It works fine once it starts, so it's not really a problem.