I will try and give as much info as possible, but I have reverted to a post-kde4.8 image where everything is up-to-date apart from the recent Gimp 2.8 packages. This is using the heanet.ie mirror.
From what I experienced, as in my previous post, what was missing is the gimp python console, (at the bottom of the filters menu). I am assuming that this had a knock on effect and some additional gimp python plugins such as GURM, GAT-tools, python-brush manager, not only not working, but not loaded (not in the help -> plugin-browser)
For reference some screenshots from another machine, also up to date, including the Gimp updates.
This one had gimp 2.8RC1 already installed using AndrzejL's script. All is working here,
Looks like the gimp update went on top of the existing files.
this is the screenshot
http://i.imgur.com/fcgb7.jpg of the bits missing on my regular machine.
If your Gimp 2.8.0 has the python console entry, then I will have to do a bit of digging, otherwise;
I will do what I normally do in such circumstances, wait a couple of days & try again. Thanks for your interest.