Need to push catch in
In our old
Ibiza the headrests come straight out with the button.
Difference with the Leon is that you then need to push the catch in through the little hole to get the headrests off.
A flat screwdriver or similar did the job.
I agree that you do need to remove the headrest with the booster seats with a back and headrest. Otherwise they don't sit properly.
Also removing the rear headrest improves visibility a little bit which seems to have got worse going from the
Ibiza to the Leon.