If it has not been opened for a while then they can become stiff.
1st get someone to push down on the front of the bonnet while you try to pull the cable, If it gives enough then when the person lets go of the bonnet it will come up to get to the catch.
If the cable is hard to pull, squirt some spray down the cable guide and just work it down the tube by repeated gentle pulling, again take the strain of the catch by holding the bonnet gown.
Sometimes I think laterally, but then I have to get up!