Passed MOT today with perfect rear brakes!!
I went last week to the local Ford garage and was lucky to meet a friendly mechanic. He sad that he nor his colleagues never ever had to replace a brake press limiting valve. According to him it is just a tube with a ball inside. It can't brake down.
The problem should be found in either the wrong brake cylinder diameter or in the rear self brake adjuster.
New brake shoes come with a new adjuster but also check the counter brake part. It should have good crisp 'teeth'
Procedure. install (new) brake shoes and then the last action should be to release the adjuster, install the brake drum and if needed bleed the cylinder.
Do not touch the hand brake!!
First press the brake pedal several times so that the adjuster will set it self to the brake pedal.
Should you pull the hand brake first than the adjuster will set it self for the handbrake resulting in not optimal braking when using the brake pedal!!
I checked the cylinder diameter - 17mm, replaced the counter brake part - new sharp teeth!! - and followed the procedure above.
Resulting in perfect brakes.... at last.