Problem 1: Original Defender seats were invented by the Spanish Inquisition.
Solution: Throw out the original seats and find something more comfortable.
Problem 2: The new seats are very comfortable, but do not fit into the original holes.
Solution: Build something temporary, that converts the new seats holes layout to the Defender holes layout.
Problem 3: After 2 years of ignoring the problem that the new seats did not fold, I was looking for a better solution.
Solution: That's the time to solve the problem and here is the story:
The problem was that the old temporary solution (that I used 2 years) placed the seats 4cm higher than the original. Also- every time you need to jump start yourself or a buddy or add water to the battery was uncomfortable. Last problem- remove the chair when you need to change the battery.
First thing was to place two stripes on the original holes of the seats
In this picture you can see one of the attachment stripes after the paint job.
On these stripes I have welded one side of the hinge as you can see here:

In this picture you can see the two stripes after paint - attached to the original holes:
Next step was to create a compatible "H" to the seat:
And to add one more point so it will be possible to attach the seat in more than one point (this applies only to the drivers side):
Then, I added the static ends of the clips that locks the seats- like the ones that locks the chambers under it.
The Drivers seat, in this picture you can see the locks of the seat (locked)

And now to the demo...
This it how it looks when the seat is locked:

Moving the seat maximum forward in order to lift the seat up:

Unlocking the clips and the seat is up high:

Giving us a full access to the storage box on the right side:
From this position it takes about 10 seconds to move the pins out and take the seat out of the car.Closing the box:

And the small noise-reduction carpet:

The carpet also adds tension to the locking mechanism of the seat.
And... Locked again!

That's it!