I had a really helpfull call from greasemonkey (Steve) today. who not only helped with this but offered help for anything that may go wrong!!! It seams the JDM does support OBD2 and has a port next to bonnet release. I have ordered a Scan Guage 2, it will fit in the dash, give me trip / milage / mpg / live feeds read error codes etc etc

Wasn't that cheap but seams a good piece of kit and a decent solution. I can also move it to other vehicles in future.

http://www.scangauge2.co.uk/