Quick update - still bug fixin'!
I thought the ending was working fine, but it really wasn't.

Loads of things were triggering incorrectly. I then thought it would be a simple matter of replacing some of the triggers, but this then broke other stuff that needed fixing. When its working properly, there should be twice as many options in the final encounter than are currently available (at least potentially - it depends on what you find during the playthrough), and the Big Ending convo that terminates the module should reflect a couple of the player's choices more accurately and trigger every time. I've now got exactly half of it working properly... which is an improvement!
On reflection, I very much overcomplicated the ending to this module. For example, the player's decisions can lead to the Big Ending convo on either of the last two levels - which is fine, in theory, but means that the ending convo has to work in multiple locations (currently three) in order not to leave the player anticlimactically wandering around. I kinda love offering loads of options at certain points in the module, but ultimately it would be much, much easier if all of the key decisions were placed in one convo rather than four different convos on two different floors. The ending would need to be written differently, but this needn't mean fewer options if it was planned properly. I think the bandit camp convo (which has nearly as many options, depending on whether you find a violent or non-violent solution) was much easier to test because it was written this way - the only variable that could affect the bandit camp outcome on another map was the Druids, but that was a fairly simple convo. I need to remember this lesson for my next module!

Right, back to it! I expect to get the fully operational version up next week.