sorry for not explaining it vey well. The chassis I'm referring to is the pcb with all the adjustment controls etc

The first pic is of the main bracketing with the outside plate where the chassis and secondary plate connect to. The second is of the secondary plate that the chassis actually mounts to. I think this ensures no solder points will touch metal on the first plate. The problem is no holes on the new chassis match.

The third pic is of the chassis and fourth is where the secondary plate slots into the other plate. In fact in this shot I have a sheets of perspex attached to the metal plate and only needs 4 holes/slots for pcb plastic standoffs to enable mounting the chassis to it.