More often than not - some second hand outboards aren't even advertised. Worth phoning around a few of the dealers. They may know of a boat that's coming in that's due to upgrade the engine.
Yammie stuff, then speak to Graeme at Mackay Marine (Aberdeen) or Yampower in Glasgow. Honda then Ardoran Marine or Clyde Outboard Services (Suzuki, Honda).
I've PM you the location of 2004 Honda 115hp.