The, what will go down in the history books as The Battle of THoFC's firewall, battle is finally over.
Shiny! New! Hard drive fitted, unable to image direct fromthe old disk to the new I gave up and did a rebuild.
The majority of config files just copied across and worked, but one major webapp is defunct, and the web server has had some major config changes in the 4 release versions of the OS between old disk and new.
The one thing I thought would give me the most pain (shorewall), went without a hitch!