Thanks Amos!

That's a good tip on the let/const. I'll admit that I default to "let" generally because I assume it won't give me any problems, aka laziness!

At some point I need to refactor the whole project, since it includes code all the way back to when I was first learning JS. Including moving across from callbacks to async/await, increasing DRYness and some of the later ES developments. I'm just waiting until I feel my code style has improved enough that I don't have to go through the process twice! But I'll aim to implement greater consistency and the code style tips I'm getting though feedback as part of that rework. All useful stuff and much appreciated!