Thanks Guys!
15sAway - that's an Old Glory Blue Moon building from their 'Sleepy Hollow' series (they may have these 18mm buildings listed under some related-sounding category now instead).
OB, we're tweaking the activation mechanics a bit for the second running of the scenario, and I'll be placing the initial Brigade positions more deployed for battle, rather than having the majority of the units arriving, and marching up to contact.
I wanted to present that aspect of "Armies Meeting", and allow the players to shake out their lines with some sort of battle plan evolving, but the consensus post-game was that this was less interesting to actually getting the main lines engaged and having the fighting commence.
I didn't regret seeing the battle evolve from the march though, as it unfolded plausibly as I watched it (I moderated), but with this being put on at a public venue, we have around four hours to get the primary gaming action resolved. Too, I'm not sure having more time for the initial, lower intensity combat to occur, justifies players waiting as they maneuver up for the main show to begin - it's almost as if the advance guard skirmishing should be separated out for another scale (for 28mm skirmishing - which I've done), and have the main engagement played alone.
So I'll be tweaking the setup for playing this again in a few days.