For those with a keen eye, you’ll notice that despite all the changes on the smoke trail effect, it still doesn’t last for the full duration of a longer arc. To change this correctly, select the “Required” module on the Smoke Trail, then in the details panel in the bottom left, scroll down to the “Duration” section and alter the “Emitter Duration” parameter - a value of around 10 should do!
I hope this helps someone as I just spent the last hour messing about with the settings trying to fix it!