After years of searching and failing I have just received a waterproof coat that doesn't look like a hiking jacket and I can wear to work. The only down side is that it isn't a winter coat but it is a standard trench. Reduced from £220 to £89 with free postage!
Here. It's slightly lighter blue than in picture but a nice suit most navy. The hood is also detachable and lined. Customer service was also great.
Thought I would share as I often see posts about finding smart waterproof coats under £100.