Another warm welcome Syd, you're doing better than me - 74 on the 31st Jan - hardly play at all these days, still got a dozen or so - all 4 string, but try to keep in touch and enjoy making the wiring looms for the BC massive 👍😅
The Darkglass schematic above doen't show a stereo jack - but that's what you need for sure and the blue audio out is shown to the wrong contact of the mono jack anyway, in fact the battery negative black is shown wrong also - to the jack tip.
BAD Drawing Darkglass