It will fit the normally aspirated 1.8 okay, but it looks like this is intended for the Turbo because the pipes are coming straight out, through a cut-out on the bumper and there are 2 tailpipes whereas the 1.8 75 has a single pipe outlet and it turns downwards and fits under the bumper.
I'm just going by what I have seen - I could very well be wrong, but I don't think I am. Sorry.
This is what the 1.8 75 should look like. http://www.amazon.co.uk/Rover-1-8L-2001 ... B0053T9RVG
This is a photo of a rear silencer on a 1.8 Turbo. See the resemblance? http://www.lyonssystemsserver.com/break ... -PTIMG.jpg