London's Favourbrook is a reliable source for off the shelf odd waistcoats, and that's where I picked up the yellow one that's almost in the photo some years ago. For those seeking something more visible, the company's web site offers a range of less sedate choices.
Use the bit of extra warmth from an odd waistcoat to extend the season for lightweight jackets. On display is a ten ounce worsted coat with navy buttons (brass might have been garish combined with the waistcoat) that needed some help on a fall morning. It's paired with gray flannels, brogued bluchers, a glen check pocket square and a gray and purple striped cashmere necktie.