The Otomobile model was the only 1:18 scale model I'm aware of and it was only done as a 20VT in either sprint blue ( 1st Batch) or broom yellow later on.
No LE ones were officially made. However, there are non-official ones made by fellow coupe owner and enthusiast, Bartek Plonka. You can find him on Facebook. They are made based on the Ottomobile models from what i noticed.
Considering you might may £150 for a full-sized basket case of a Coupe, buying a model might be a better investment, same great looks after all, negligible running costs and no Coupe-paranoia (apart from accidentally snapping off the mirrors )