Rear Seatbelts in an early tintop

I have searched but i cant seem to find the info i need.

I'm looking at fitting some 3 point static seatbelts in the back of my 1979 GTI

I think I've found some that will fit (SECURON 200 ) but am not sure where the 'end bracket' mounting point is in the golf. There is a hole capped off with a plastic cross head screw (I've seen these before in beetles where the mounts were fitted but not utilised) in the boot area, each side under the parcel shelf side supports. There is a point under the back seat for the buckles but I'm not sure where the 3rd is. Does anyone have a photograph handy. The Car is currently 50 miles away so I don't have the opportunity to take a look very often.

Thanks in advance.

Dan

Only ever fitted some to my 1978 Scirocco as the car never had any fitted but like you I had plastic screws in 2 of the holes, I removed them and the fixings was all there, the 3rd fixing point was in the c piller underneath the head liner material, I had to feel around to find it, I then pocked a small hole to check then carefully cut a hole to  fix the seat belt.
Try googling and image of a car with rear seat belts to give you an idea roughly where it may be?  

Thanks for your help. I was going to with the 3 point ones that come over the seat rather than the 4 point fixed to the C pillar.

It's the lower fixed point location I'm after, the one that's on the B pilar on a front seatbelt.

Dan

My fixing is just in front of the rear wheel arch, remove the back seat base and you should see it?
Found a picture, it's a cabriolet but the front fixing is the same.
Has anyone converted to a 3-point seat belt for the rear? | VW Vortex - Volkswagen Forum

just re read your post… The fixing in the boot is also pictured in the link, not sure if using those fixing is safe and if it will pass an MOT as the design really needs to be fixed to the c pillar like the way VW designed it?