Okay so today wasn't so great (though not as bad as I'd worried). It was horrible weather before we even started--that kind of pervasive rain that soaks you to the bone--but it seemed to be tapering off as we set off. Within five minutes, we were both soggy, and Lola had begun begging to be picked up.
I didn't want to abruptly end the session because of a 'little bit of rain', but in hindsight that was a bad idea. For now, medium/heavy rain means playing rainy-day games inside and going out later.
The sounds of cars going past on the main road were amplified by the rain. A woman suddenly appeared in a doorway, holding a popped-out umbrella. A grown man jogged fast from the boot of a car into a building (Lola growled at him--the only time she did growl, though she thought about it with someone else too; a woman that ran across the road to her car on our side of the road).
She kept her head, but barely. She was really anxious, and spent about 80% of the time we were out in my arms. The rest of the time, she was asking to be carried.
Our walk later went well. We got a chance to practice BAT three different times, with four different dogs. And I'm pleased to say that she didn't bark, growl, lift her hackles or anything at any of the dogs - even a labrador that 'suddenly' appeared out from behind a tree with a fellow dog.
So all in all, despite a shoddy wet day (and the farmer's market being a disgrace - I don't know if that was because of the weather, or if it only ever sells flowers and chocolate bars; even the guy who sells eggs in the normal market wasn't there!) Lola did okay. She was definitely way more stressed than I'd like, and has been venting that stress by harassing me to play with her for the last couple of hours (first play catch/fetch with the toy, then attack the toy on my lap, then chew the toy on my lap), but she growled at only one person, and made a couple of good choices in looking back at me for reinforcement rather than reacting to provocative stimuli (like the woman in the doorway, holding the umbrella).