My hood wouldn't open unless I wedged the release lever open and then
tried it.  Sometimes the little hood lifters stick.   Then after a
while it wouldn't open at all and after forcing the cable to open it I
noticed that the second piece of cable from the first latch to the
second had come out of it's fixings and wasn't actually doing much.
After a bit of playing around I got it all installed properly and now
everything works as it should.  There are two sets of adjusters - one
on each cable. I suspect that the dealer will simply quote for a whole
new cable assembly as that's easier and more profitable than
troubleshooting the problem.