It's been taking a long time to get through some of this code, much longer than I thought it would, but I have been chipping away at it slowly, and tonight I managed to get a good few hours in, so the results showed that.
It might seem trivial, but building on the "combat mode" or "not combat mode" in the last update, I have been working through all the code to split out the party from a single sprite into individual characters, each occupying their own location on the map - and the same for all the various creatures that are in an encounter. Next up more interface work to give some sort of options for a player to choose for their characters - and finally how to render it all correctly so that when the focus changes from one character (or monster) to another, everything else is still correctly rendered in the right places on the map. The basics of that are working now, so I'll start to build out both player options (I'll do movement in combat next) and then I think I'll start to work on super basic attacks/defences from players and monsters which the basics should support without too much change - then with the utter simplest of options, it will be time to give some logic to the monsters to be able to determine what they need to do when it is their turn.
The fun I'm having right now seeing this all come to life is amazing and utterly exhilarating - I can't wait to build this out.