The Pit (Of Knowledge)

Located in the poshest part of town, this is a nice summer cottage belonging to the Wiffleblat family. Not especially large (for a wealthy family's summer cottage) but has a nice private kitchen, with three stories if you include the attic-space that could easily be turned into an apartment without an excess of work if desired.

Sebastian has sent the family servants away and instead just houses his assistant/bodyguard and locally hired cook and cleaner.

A small building behind the cottage is Sebastian's private workshop, where he can do ill-advised experiments without potentially-disapproving faculty watching. (No one saw his “accident” as a result, and this still don't see it now…)