Hi Craig,

29 bar is the pressure at which the system unloads. If it is achieving 29 Bar
and as you say the discharge gas pipe is to hot to hold.

Then the problem is not with the outdoor units it's at the indoor units.
1. Either your over charged
2. The SVK boxes are not opening
3. There's a blockage in the pipework
4. Your interconnecting cables are crossed and your not looking at the correct indoor units. IE. the cable may be going to X indoor units but the pipes are going to Y indoor units .

Have you checked these options.

Do you have a manual for this machine. It is possible to connect a remote controller to terminals 3+4 at the outdoor unit and investigate the temperature sensors at each individual indoor unit.