Yeah I think you are right mate,
it must be for the diesel, says Golf Jetta 1600td on the box!
I should get this sorted by wednesday!
My water temp light had been coming on and the mechanic suggested that due to the crunk/oil in the water tank the sensor in the tank must be covered hence the mixed signals. I guess I will find out soon enough!
Also yesterday, I was running the engine with the bonnet open and noticed that the fan kicked in at
110 degrees.........is that the normal temperature the thermostat opens? A friend said that MK2 GTIs issue thermostat opens at
87 degrees? 
Many Thanks for all your responses,
Goops