From underneath, remove the stone shield, and you will be able to access the two 10mm bolts on either side of the bonnet catch. Given the reduced space, you will probably find it easier with a ratchet spanner, as a ratchet socket will be too large when the bolt turns out. Then, prise the bonnet catch away from its mount by levering under the plate where the bolts were. Ideally this will disengage the snap-together connection between the bonnet catch and the cable from the key. Then, from the top, pull up the bonnet - it may require a bit of effort if the snap-together connection is still in place, and might also break some of the plastic components, so better to ensure that the bonnet catch is prised away from underneath before forcing the bonnet.
captainscarlet
August 2009