low compression on k series 1.4 cyl 2 rover 25 52 plate?

hi i have a rover 25 and the headgasket had recently gone before doing the headgasket was running on all 4 cylinders i have replaced the headbolts cambelt headgasket waterpump etc and torqued the head down to 20nm +180' +180' valves on the cylinder head have been pressure tested and the head was skimmed i did try the headgasket change without skimming it and had the same problem on cyl 2 so replaced the gasket again and had a skim and tried again with no joy compression is at 40-60 psi depending on how tight the headbolts are all other 3 cyl are at 150 psi any ideas ppl?