I was missing some config changes from
http://blog.loftdigital.com/running-phpunit-tests-in-eclipse-pdt. 

1) Added PEAR to build path in your Eclipse Preferences (sec 7)
2) Added PEAR to the include path for the project (sec 8)

Now 'Run Tests' and 'Run All Tests' isn't greyed out on project/file
context menus.

Can't run any tests though, I get a message stating debugging directoive
needs adding to php.ini, so close...
MakeGood is now running tests when project files are saved - wow!!
Configured xdebug as per http://xdebug.org/wizard.php.