astra mk4 1600 club misfire?

i have an astra 1600 club 8 valve 1998 it started ticking on acceleration, on investigation i found that it is missing on number three cilinder (counting left to right)it has a good spark new leads and plugs (which i have swapped about)compression is good it has recently had a cambelt water pump and adjustment pulley,head was skimmed due to blown head gasket...all costly,but this has me weeping.

can anyone help? Or a lotto win that would do!!!

Andy shrops
June 2008