The spring one has siezed and has noisey bearings and the eccentric also has noisey bearings.
I've found a few places that stock the spring tensioners for around £50 (GSF, Kevin Cooper SW) but im having a bit of a problem trying to source an eccentric one, I was suprised when GSF said they didn't list them.
One of you must know somewhere that stocks them cheaper than the main stealers!