I remain unconvinced! Btw it was 123.8bhp at the wheels, how does that compare?
123.8 bhp at the wheels does NOT correspond to 162 bhp at the flywheel.
That's way to high an amount of power (23.6%) to be lost in the drivetrain in a transverse front wheel drive car. The right number is about 15%, or even lower. What that says is that there's serious questions about that dyno and/or its operator. You can't rely on the numbers he's giving you.
However that doesn't answer the question of why your car produced less power than other cars tested on the day that it shouldn't have produced less power than. People can suggest possible reasons, but without evidence of which of the great many of them it could be, you and we have no idea. All they suggest is what it might be worth you investigating first.
Looking at the dyno chart you posted your car looks like it would feel strong in normal road driving. It has a lot of torque at low revs. Rather than your car having a fault that's subtracting power, it looks more like its tuned for torque rather than power. That points the finger at something like cam timing.
Was the cam belt put on one tooth out, or somehow incorrectly? Is the VVT fully advancing?