So is the bite point moving inwards over time/as the pads wear? If so then its the brakes not the pads where the issue lies. Could be sticky pistons/air in the system/not enough fluid in the brakes causing either the pistons to not be pushed out or excessive negative pressure in the reservoir sucking the pistons back in.
If you pump/pull on the brake lever in quick succession does the bite point move?
Yes that’s right, I will try putting the old pads in and pumping the lever see what happens.
The brakes are not that old and don’t leak so I am assuming there is plenty of fluid in there. Last time i putnew pads in i had to push both pistons back in and they moved quite freely.