is there an airbag sensor in the front bumper anywhere? thx

No.

The crash sensor in central in the centre console, under the dash.

And on the floor under the seats.

Just out of interest, what's the part which looks like a push switch behind the plastic trim next to the square fog light? I've only found it on the nearside, but that's only because I've not taken the offside apart, so it may be there too.

It's a black cylindrical smallish object, which clips into one of the fog light torx retaining bolts. I assumed it was an impact sensor, but judging from the replies above, I guess not.

Cheers

Rob

I would think you've spotted the outside air temp sensor.

Ah, makes sense. Thanks.