Hi
The phase 2 has a pretty bad bonnet release lever under the steering wheel. It basically has a very silly plastic round piece that holds and pulls the end of the metal cable and it has very little strength in it at all. When its failing it will go gradually and then just snap. While this is a mega pain having to buy a new cable AND handle assembly together as one part, there are two ways at looking at this:
1) It's a really awful design and when replacing the handle, you shouldn't be forced to buy another cable with it even though its ageing and going to also snap in the future
2) It' breaks in a rather convenient place designed to be weaker where you can still get your bonnet open (before the physical metal cable itself snaps inside the bonnet forcing you to smash in the headlight).
Whichever way you think about it, you clearly need to get the bonnet open with minimal damage so grab yourself some mole grips.
This is one after snapping. You can see the cable just hangs loosely. Clamp on your grips as shown:
Using something very big as a pivot (I used a ratchet screwdriver handle) lever the cable over your pivot so that it is pulled in the same direction / motion that the handle would pull it:
Your bonnet should now be released. Note that this only works once or twice before it starts becoming harder to open. You will need to replace your cable ASAP. The replacement cable comes with a new handle and fitting bracket all as one part so you will need to open up the engine bay and loosen several fittings in order to remove the old cable and its protective cover. Before you pull it through into the footwell, attach some string or thing strong wire to it so that when putting the new cable in, you can just pull it through the bulkhead.