Was the engine running before you started this job or had it been damaged?
Yes the engine had been running well, but the car developed a water leak, which I mistakenly thought was the cylinder head gasket. I stripped the engine down to find the gasket intact and the engine in good condition. I did a quick decarbonise, fitted a new gasket, and a new thermostat housing which was leaking, but I have a problem with the valve timing owing to no timing hole in the bellhousing.
There should be a hole on the edge of the casing. See diagram below.
There is no hole on the edge of the casing
Why the poor service rating.
I have given you the official repair instructions from Vauxhall.
Did you look at the diagam for the location.