For many years I travelled the UK on business, summer and winter, by bike -with a suit.
No particular advice on makes, get what you are confident with for warmth and waterproofing, but I just went shopping for a textile jacket and trousers with my business suit on and bought something loose enough to comfortably fit over it.
I have found salopette type trousers best as it's easy to tuck the bottom of the jacket in and avoid jackets that had the waterproofing as a Goretex membrane as a liner. The problem is that it may keep you dry but you get a soaking wet, cold and heavy bike jacket. I either use a one piece oversuit or dig out an old Frank Thomas Aqua jacket. About 15 years old but the outside is still 100% waterproof and as it does not soak up water it dries quickly.
The biggest problem I found was finding boots that were totally waterproof and long enough so my trousers did not slide up over them. Eventually discovered plastic riding horse riding boots. Totally waterproof, cheap and smart enough that I could get away with leaving them on under suit trousers and they just looked like normal shoes. Downside was not that warm and no crash protection - but you can't have everything.
Never had any problems and often I would arrive at client after four hour ride in rain, strip off bike kit in car park, change boots for shoes and swap the kit for my briefcase in the pannier.
On the odd occasions when the client walked back to my "car" with me they were amazed to find it only had two wheels!!.
£98.00 . The most annoying thing was that my Sister-in-law got switched back to long haul flights two weeks after mine arrived.
