Does it matter which side the meter tails are connected to a 100A consumer unit main switch? It's a conventional four pole (TP+N) isolation with no integrated overcurrent or rcd devices. The tails have been connected to the bottom (for what I assume is cable routing convenience) which presents no particular problems with wiring the board as it's split in several ways. Everything else is connected conventionally and I can't see that it can have any electrical or safety consequences, but I would be interested in some professional opinions.