What containment would be best for this installation?

[Davisonp]

I would opt for steel conduit if MICC isnt stipulated, primarily because im happy working wity conduit, it doesnt cost too much, and i would be happy that i could be competetive.

I would choose steel over plastic because of aesthetics and protection. Although platstic is far far quicker and easier to fit.
MICC (pyrotenax) would look the best by far, but its whether you would win the work because of the cost and time taken to fit it.

I am starting to think steel conduit this is the best option for this church, certainly in the main hall.

 

[Davisonp]

there is no such thing as a 100mA TD RCBO. What earthig system is prsent, do you need additional earth fault protection at al???

Yes, what I had seen is a MEM 100ma RCBO, and I had assumed other manufacturers would have the same thing available. Further investigation has reveled that what I had seen was a MEM EATON 100mA add on to an existing MEM MCB to make it an RCBO, and only available on Ebay, so I will not be using that.
I guess I will have to put a Wylex 100A 100mA Time Delayed RCD in it's own enclosure near the main distribution board.
The earthing is TN-S (I have been told).
I have not had chance to investigate the building as an electrician yet, (attended a wedding a while ago, but not looking at the building then), but I want to have a good idea of what is required before I take a look at the building.

The sub main does not need to be RCD protected by regulation as it is going to be surface mounted, but the client (sound system installer) has asked for an extra RCD on the sub main. I will suggest that they do not need one and see what they say.