As there was quite a bit of interest in this thread I thought I'd snap a few "after" photos. As you can see, I've rewired throughout in PVC conduit.

Two duplex recepts. ("twin socket outlets" in Brit-speak) are now in the office in place of the previous one-outlet lash-up:

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This is the area which formerly had "T&E" (NM-style) cable draped everywhere to feed the office (the pink-painted trunking now contains just the CCTV cables):

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A couple of shots of the same areas pictured above, as they are now:

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The central aisle, not pictured before but it had a variety of fluoro lights at all different angles and with the same sort of lash-up wiring. Now just four 8-foot 100-watt fixtures in a line:

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