Well I have my WD MyBook World Edition II now and "it just works"! :-)
To expand a little, I plugged in the power, connected the ethernet lead and turned on. Using 'arp' I discovered its IP address and then was able immediately to connect to its web configuration pages.
I have enabled ssh and nfs and am now able to log in to the WD box's command line (seems a pretty standard Linux system) and can mount nfs shares from the box. What more could one want? (Well, a little, see below.... )
Now the question, I use dnsmasq on my desktop system (well that's where it is at present) to provide local DNS on our little network. It's set up so that DHCP clients can be accessed with just their host name or with the domain suffixes. E.g. I can access 'maxine' or 'maxine.isbd.net', or C475IP or C475IP.isbd.net.
However the WD box registers with dnsmasq as 'garage.local' rather than just 'garage' (which is the host name I have given it). Can anyone suggest why this might be and/or how I can fix it?