Mind you, they seemed surprisingly at ease around futuristic technology for someone who lived in 1888.
It doesn't surprise me that Madame Vastra is at ease---Silurian technology was shown to be far more advanced than the Earth technology of the year 2020 (as we saw in the Silurian episodes in series 5). So even if the Demon's Run technology is more advanced, she would probably view it more as "Wow, more advanced technology" rather than witchcraft. Maybe she took some advanced technology with her when she moved to London, so her companion would also be familiar with it.
I heard about that shift in production order. I wonder if they rewrote anything else---Amy and Rory seem surprisingly cheerful for people who had their baby snatched (unless they were rewritten to be more cheerful when the episode was moved).But The Curese of the Black Spot was supposed to be part of the second half of the season and was moved to the first half rather recentally, some time this year I believe.
A related note: if/when Amy leaves the Doctor and returns home, she's going to have a fun time at her next (medical) doctor's appointment:
M.D.: "Hmmm...so my examination indicates that you've given birth before. So....where's the child?"
Amy: ""Ummm........."
I guess she'd have to lie or something. "Ummm...it was born stillborn. Then, the hospital burned down, along with all the related records. My old doctor got hit by a bus and died, so you can't ask him about it either. Also, I never told my parents about my previous pregnancy".