Are the skirtings off the wall???
Are you sure they are Nails, and not a special type of screw in worms for breeze/thermalite blocks, under dot and dab and dry linning -we used them a lot, once fixed forget about taking them out. a straight pull out will bring a lot of the block away, if nails they probably rusted in and have an even better hold, thats why rusty nails get a better grip.
Stan
Are you sure they are Nails, and not a special type of screw in worms for breeze/thermalite blocks, under dot and dab and dry linning -we used them a lot, once fixed forget about taking them out. a straight pull out will bring a lot of the block away, if nails they probably rusted in and have an even better hold, thats why rusty nails get a better grip.
Stan