I followed the guide to SPICE simulation on the KiCad site, and spent a while figuring out why my non-SPICE Vcc rail wasn't working (you have to use a SPICE VDC source instead for it to be recognised). But putting test points in the circuit and re-running the simulation helped me figure out what was wrong.
I think it took me about half an hour to get there. (I do have previous KiCad experience.)
This has definitely made me think about doing more analogue circuit design in future!