Morris Minor Owners Club

Where safety is concerned it is purely your decision and nobody is going to criticise you. You can be doing all the right things and some idiot will drive across in front of you. I have fitted static front belts in my 2 door MM and I will probably change them for inertia belts. The top mounting point on a 2 door needs to be on the rail under the side window.
If you search through the message board there are several topics on how to fit rear seat belts.

I have replaced my static belts with inertia reel belts and they seem to work fine. I do not intend pranging the car for a difinitive test!

I fitted inertia seat belts to my 1950 lowlight tourer, original BMC chrome buckle type.
I can now hit the speed limit without fear.....

I won't ask how you took that photo. Oil pressure is a bit high

Where did you get that KPH speedo???

I had mine doing 80!! Of course that was with an electric drill when I fixed the speedo.........

A starter to get the debate rolling....

No easy way of fixing shoulder strap bits on a saloon without putting them through the flat sill below the rear window. Worth adding load spreaders to all of the mounting holes. These would be 3inch squares of steel plate that the bolts go through and in the case of the rear window sill panel it would be worth running a long strap sideways to spread the load since this area isn't particularly sturdy. Better than nothing, but, if you want a sturdy top link in the system then it is worth spending some cash to have a bigger bracket/strap welded in across the whole back end. After all, you are only ever going to need them once!
The fronts are a lot easier.

http://www.mmoc.org.uk/viewtopic.php?f=6&t=31311

My efforts for fitting rear seat belts.

I've fitted fronts too..and maintained use of the trafficators and it's a four door. No piccys though.

For the front seat belts I drilled a hole in the top verticle with a nut welded to a 4'' plate same width as the pillar.
Then the inertia winding mechanism bolts to the floor directly in line with the top pillar.
Another nut and 4'' plate welded to the centre propshaft tunnel secures the other end.
Just one thing to look for is the length of the belts especially for the passenger side.
As the rear propshaft tunnel anchor position determines the length of the belt..

As for the Oil pressure it was a cold day and it dropped to 40psi soon after my backseat passenger took the photo

Thanks very much for your comments and advice, I really appreciate it.
I feel much better knowing that others have fitted belts in their car safely and will be taking in all the advice given.
I have found a website that sells all different sorts of belts so hopefully before long will have the children strapped in safely.