Mainly, noticing that the neutral travelled from the double-pole isolator, half-way along the garage, through an unswitched FCU, past a light switch and then back the other direction in another piece of twin-and-earth. Effectively, it's a continuous, unswitched, unfused conductor that's gone six metres to end up mere millimetres below where it started out.I was pondering what might be the motivation for wanting to use four singles in conduit rather than two T&E cables (possibly not in conduit).
My general instinct to optimise says that ought to be unnecessary, though I do understand the arguments against going four-wire instead. (-8