[Simon Gerrard]

Check the gaps on the spark plugs, make sure the elctrodes aren't warn out.
Can't see a picture

Simon

[MAX Carpets]

Friend has just done a compression test, low on one side. Said he thinks its the head gasket. Does this sound about right?

[Simon@arenaclean]

Could be valve or valve seat, maybe need re-seating if they are pitted or scored, that is generally what cause a drop in compression. Change head gasket any way but check valves at the same time.