Hi Ewen
As Ian G and Wild E have posted. The Milltek is about the same dimension as my piper so unless you can jack it up 3ft off the floor or have access to a 4 poster the best way to fit is remove the bottom gearbox stabiliser which will allow the engine and box to waggle backwards and forwards. Then If you or a neighbour have a manhole in their drive put a piece of wood across the manhole with the manifold loosely tied to it in the manhole. Tie a longer piece of string to the manifold then put your car over the manhole fish out the longer string through the back of the engine, untie the manifold from the wood and pull the manifold up into place whilst rocking the engine to get clearance. You shouldn't need to remove the driveshaft as there is enough room.
Barry