Hi Tristan,
I have had to do the exact same job and it is a pain. Unless you have access to a garage, a set of ramps or a lift then forget accessing the bolts from underneath, an extension bar will help but the angle on the coupling makes it impossible to get the socket on for a good grip. I too was loathe to take the injection system off BUT! it is not as hard as it look, basically it is near enought the same as a carb model just with more wires. You cannot get the wires back in the wrong place, all the plugs and receptacles are keyed and are different sizes. If in doubt label them up! The Inlet Manifold will come off complete with the injection system, just lay a cloth on your wing and roll it over onto that, be aware of drips of petrol that may escape. Also! another important thing, you will see on the bulkhead the fuel inlet and return pipes, these MUST be replaced in the same position, otherwise the car will not start and when you undo them again you will get showered in petrol! So basically thats it, the whole procedure took me about 3 hours start to finish. Hope that helps!
Andy