i have a series 3 alpine (1725 and overdrive) but the bonnet keeps popping open ( to the latch) when i drive her.
any clues as to how the spring and bolt fixing work i have read all my manuals and for other cars but to no avail as to the right way to adjust the bolt.
any advice gratefully received.

The plunger needs to be long enough to latch into the lock. You can adjust it by undoing the nut, and turning the plunger in or out. It also needs to be lined up correctly; adjust this by loosening two bolts and sliding into position.

thanks v mad , i will be spending most of tomorrow trying to tie up loose ends and will look at the catch then.

Michael, try not to get the catch jammed as there is no easy way to release it from outside.
You dont have a location in your profile? Are you norf or sarf?

I am Sarf Of Sarf London (we moved into deepest Kent last year from south london.
Ive had the problem of the release not working and found that a spatula and a piece of plastic tile trim did the trick. i havent tried the bonnet catch today but have been successful in fitting the carpets properly and also reset plugs points etc and finally found why the car stalls when the air filter is fitted (the kandn (ipresume it is )on the webber twin was blocking one of the down draught holes so i drilled and filed it out of the way.also reseated the carb as it was sucking air at the joint with the manifold. A successful day.