I should have looked at the owner's manual more closely!!! It is just to the left and slightly above the oil filter. Its fairly obvious after you remove the exhaust manifold cover plate.
My next concern is that after following the instructions to the letter, ie remove plugs and drain system, replace radiator plug and flush system until clear water comes from engine drain hole, replace engine plug, remove heater hose at tap, fill system until coolant comes from heater hose, re-attach hose and complete filling system, I could only squeeze in 3 litres and the manual says it holds 5.3. Its a bit of a worry.
are u using a gregorys manual by any chance? They are out quite a bit on some things of mine... One thing you may want to try is to let the car run for a minute or two to let the coolant circulate thru the rad and engine. Make sure u do that with the cap off tho, and dont rev it, otherwise u lose all the water.
Another point to mention is that the overflow bottle has a min and max level on it... they are faint, but theyre there... make sure it is filled to the max level on that one too.
Just using the owner's manual that came with the car.
I have been thinking about this and given the height of the "drain" plug on the engine block and the instruction to flush the system until clear water comes out the plug hole, I presume that there is a residual 2 litres of water below the level of the plug hole.
I bloody well hope so anyway because I have driven the car and temperature is OK.