Piano choice. Thoughts please

[jolly roger]

  Had a
>little problem - using the una corda pedal would slide the action a little
>forward, so that the end few treble keys fouled the key slip rail and would
>stick down.  Evidently someone had seen ths before and tried to fix it as
>there was a slip of leather stuck to the front of the keyblock to push the
>slip rail out a little. Not enough though.  Easily fixed with a small strip
>of felt stuck to the front of the action to prevent it moving forward. 
> 
 Hi David,
                Solve the real problem and bill the customer accordingly.
The problem is one of the following.

1. The unicorda arm and or the trap work brackets. The unicorda arm is
twisting and pushing the frame skewed.
2. The unicorda slot in the bottom of the action frame is badly worn.
3. The cheek block guide brackets are badly worn. Get a machinist to
duplicate them, and replace.

Any and or all 3 can be the trouble.
I have found the shim fixes just comes back to haunt me. FWIW.
Regards Roger