Hi guys, just need some advise from someone. I've knocked through from the lounge to the kitchen area, fitted the door casing which lines up with the skirting board, the wall is concrete block with 12.5mm plastrboard which has approx 10mm adhesive to it. Unfortunately block wall is leaning 20mm out which therefore runs approx 10mm beyond the door casing, the only thing I can see to do is to cut the existing plasterboard back further along the wall to try and gently bring it into the casing. Can I use backing plaster next to the plaster board without any cracking?