I concur with Big Rob's suggestion of the FA or McAlister in brown.
If you wear sport coats & tie a lot, the McAlister might bridge the gap a tiny bit better. I'd also suggest (if you want to dip your toe into the shell water) the Cambridge or MacNeil in burgundy are excellent.
I realize there are people who preach no bluchers with suits. But, in the US anyway, there is ample precedent for wearing dark colored gunboats with suits.