If you have a Pressure Relief Thermostat - PRT - (Item 17 in the Rimmer drawing), then you need one of these:
http://www.ebay.co.uk/itm/NEW-Stainl...QAAOSw-pVZlWWL
which replaces Item 7.
If you don't have a PRT (there's no Rimmer drawing for non-PRT Turbo system), then you need one of these:
http://www.ebay.co.uk/itm/MG-Rover-N...8AAOSw2gxY0xL9
Item 3 in the drawing is the small bore hose going to the turbocharger.
TC