*HELP* 2006 Urban Fox Misfiring. Where is TDC Sensor ? Changing coil pack & plugs didn't work.

[D1CKY]

I have a 2006 1.4 Urban Fox on 42k miles that has just started misfiring and has a engine light illuminated down the bottom right of the instrument cluster.

I have plugged the car into VAG COM/Diagnostics and got back a 0304 code telling me cylinder 4 was misfiring.

I then went to change the coil pack as it was one of the parts listed as a possible cause on the Diagnostics scan and is a common VAG problem.

I fitted it and and nothing changed, i then changed the plugs for OEM NGK ones as they had never been done.

The leads are ok.

My next step was to check the TDC Sensor is functioning as it should and give it a clean if required or would it bring up a separate code ?

I cannot locate it around the bell housing/flywheel area (I must be blind).

Could it be internal and a gearbox off job ?

What is the chances it has a camshaft sensor instead ?

Next up is swapping injectors around too and see if the problem moves.

Then the dreaded compression test :-(

Assistance welcome.

Fire away with ideas