30K?!?!?!
I hope that's not £'s - if it is, it should be a pretty big screen...
As for the studs in the wall, I've seen the galvanised steel studding, but not heard of it in aluminium. Even the steel stuff I would be wary of fixing to - the steel is pretty thin & it's easy to strip out the screws. It's designed to support the weight of the plasterboard, but I don't know about anything else. Best thing I can suggest would be to find out who makes the studwork, and check the manufacturer's website for the specifications.
I've never known plasterboard to be 18mm thick either, unless it's a double layer of 9.5mm. Plasterboard is usually either 9.5mm or 12.5mm thick.
Hope someone else can help further.
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