Stretched bonnet release?

[Sidewaze Samm]

Tried to open the bonnet on my lad's zed (pre-facelift). Couldn't pop it up without pulling the release lever fully, while he pushed down on the bonnet, over the catch.
The bonnet sits at the right height and once it released and popped up, it opened fine; it seems to me it's possibly a stretched cable, which I believe comes in more than one section.

So any suggestions on improving this before it gets worse?
Is one section more likely than another to be the problem; which one?
Is replacement the only fix, and what does that involve?

cheers

 

[pr117]

Actually it is from two pieces, check that connection first.
Right hand front corner.

 

[Lance]

That black junction box should be attached to the body for the cable action to work.