In reply to Garston:
Hi Chris,
Me and some friends climbed the dam, albeit about 5 years ago now but a few points i remember.
We paid i think ~10 Euros for the ladder key to access the route, We didn't lock it up as another team were setting off after us.
I don't believe its possible to use just one colour.
Both the bolts and holds were in good condition when we climbed it, and it wasn't new then, so i would guess it's aged well.
Hopefully someone who climbed it more recently can be of more help.
I know it gets allot of hate for being just a climbing wall, and the usual "if i were going that far, why not climb real rock?!" types, but i took it at face value, was my second multpitch and i loved every minute of it. I would even consider a long weekend trip back despite me being more of a trad only climber now!
Enjoy!