try to get the gromit out if you can, but it'll never go back in! Mine doesnt.
poke the wire through and up slightly so you can grab it. then in engine bay remove the two bottle to help you get behind the sound proofing/heat shield material thingy.
Not too difficult if you know what you are doing.
If you get a torch, and lie on your back in the passenger footwell you will see the grommit, with the bonnet release cable going through it.