That part made me shudder a little. Not more "family" friendly stuff. But we'll see next week.
The kids in The Snowmen weren't bad, so it's at least theoretically possible to have a good episode with kids. Plus, the nanny aspect is part of Clara's character, so it's important to explore it a bit.
That being said, "We'll tell Dad" doesn't strike me as the most plausible tie-in.