Alright, It worked!
What i did:
My original install was on my secondary drive (D:) in the root folder. D : \ Rocksmith 2014
I copied out my dlc folder to another location.
Uninstall through steam
Install through steam - Steam asked me do i want to create a new directory (on my secondary drive) which i dont think happened last time, but whatever. It put the new directory in D : \ steamlibary \ steamapps \ common \ Rocksmith 2014
Loaded the game - everything was fine - I didnt need to use justincaseyouneedit patch. Steam put all the original DLC files including cherrub rock back in - I had some other legit DLC from when i purchased the game. Bob Marley, Elvis etc.
Copied my cdlc back to the new DLC directory and ALL my files showed up. Obviously the ones i couldnt see before were all at 0% complete. All my other files kept their progress.
Closed the game, downloaded another CDLC and put it in the directory to check it works and it has. Its showed up in the list.
Hope this helps someone
EDIT: all my original dlc and cdlc worked but when i tried to play a 'new' cdlc it just froze. I still got the tone and just a picture of the amps. I ran the patch file and that has sorted it out.