The device name is visible in the network.opts script: it is in
$DEVICE. You could select what to do based on this variable, instead
of deciding based on $ADDRESS.
-- Dave
Aaargh - it's so obvious now. I totally missed the $DEVICE variable, possibly because the HOWTO and all the documentation I've seen (as well as the Debian example network.conf) uses $ADDRESS as the example of how to check for different configs.
Thanks for the help, and apologies for the dumb question.