So, out for a drive today in the GF's 500L and the AC is not as good as should be, clutch is pulling in but is def low low on refrigerant.
Is is R134a and does anyone know how many g please.

The worst part.
Its been serviced in May, when looking at the compressor and piping I noticed the air-cleaner cover bolt loose on RHS.
removed the bolt on the left, pulled back the filter cover housing and found the rear plenum chamber support 'broken' where it mounts to the rocker cover.
Looks like the inserts have been spun too.

Has anyone seen this, is it a design fault of function of the garage mechanic.
Please see attached pics.
How easy is it to change the rocker cover and complete plenum chamber please.
Thank you.
john.

Certainly not a failure, some charlatan has taken a saw to it!

I have the same dilemma of wanting to remove the plenum, because the valve cover gasket on my wife's twinair is weeping slightly. But due to the design, it's a big job to get to the point where I can remove the cover. I'm assuming the whole intake manifold assembly has to be removed, so that would be a second gasket that has to be replaced. For such a tiny leak, I'm struggling to find the resolve to do it.
Cutting through the support bracket would certainly make it a lot easier, but that's not the method for me. Like the OP, I would appreciate any advice from anyone who's done the job properly.