That looks a good solution, I reckon if you reversed it so that the bit you unclip was at the beam end rather than the bonnet end that wouldnt be too hard to open to refuel.
Would still fit a secondary hold down, dont have a photo and cant get buggy out at the moment so will try to describe what I have done.
Got a length of incredibly strong nylon cord, some eyelets and a clip (all from a boat chandler)
Fit an anchor (not a boat anchor

) to the bonnet and tie a length of cord to it with an eyelet if required, fit the clip to the end of it.
Fit an anchor point to the car and either clip to that or use another cord with an eyelet for the clip.
On mine I have an eyelet fitted that lets the bonnet open a few inches, far enough to unclip it, and another that is left clipped that lets the bonnet open enough to fill but not slam back on the screen. But mines a Doon and the bonnet opens differently so the long cord stows OK
Being a bit anal I also have a standard latch to let it part open as in a daily bonnet, a Scirrocco spring latch and a bent stainless catch plate
Hope that made sense
Dave