My brother's car - but I always seem to end up doing work for him. 

Not asking for advice but putting this here in case it helps anyone in future. Car (2008 1.8tdci) has oil leak from vacuum pump - not where it joins the head - but from the rivetted on bottom cover. So car needs regular top ups of oil - lots of it. But then bonnet catch got stuck. key turns and feels right but bonnet does not pop up. Read tons of stuff on internet about ways to get it open but none of it helped. So this is what we did - desperate measures - but car needs more oil or can't be used (it also needs the oil leak from vacuum pump fixing but that's another job).

The radical solution. Using a hack saw blade held in a thick rag I sawed a section out of the radiator grill around the badge. Then I can get my hand behind the lock and pull back the two tabs so i can remove cut section of grill and leave lock dangling. More wrestling with this would not open bonnet. So next I used some big cutters and cut through the lock cable inner and outer. The idea being to get mole grips on the inner cable and turn in anticlockwise further then the lock barrel allows the key to turn. At this point I can't get grip on inner cable as it's not sticking out of the outer cable. So I just pull the outer cable off - this came off quite easily, just leaving the inner there. Now I put mole grips on inner cable and turn and bonnet opens easily. When doing this you need to keep the cable pushed towards the catch. This is part of the antitamper feature so that if sometimes tries to break into the bonnet by pulling or twisting the lock, the cable is not pressed hard enough against the catch to engage.

But at least the car is usable again, with a big hole in grill and mole grips in glovebox. 

First pic shows grill. second pic (yes I know it's a poor pic) shows the catch in Red and the cable end in green. (the blue and brown wires are from me rewiring the high speed canbus but that's another long story)

Might help someone who's desperate. 

 

 

 

Hacksaw is quite desperate LOL But, in the same vein, if someone gets to this thread via a google search, here's my story...