Quote Originally Posted by DirtDiva View Post
I need more pictures and less words! I suspect it's cable tension rather than limit screws, seeing as shifting is equally buggered in both directions. Now I just have to figure out which bit is the adjusting barrel. I'll have a fidget some time I'm feeling adventurous - guess I can't make things too much worse... Cheers.
The adjusting barrel is a thing that the cable housing stops at which can screw. It could be located where the cable from the levers meets the frame or it could be where the cable enters the derailleur. Turn it so that it sticks out more.