[simonjedrake]

Evening
This part of the forum is a pretty dead end so no-one looks here - next time try posting in the main section one level up.

Ok, so re your two questions:
1. If your model is equiped for a SIM, the SIM Holder will be behind a small black plastic cover that levers carefully out found low down in the Passenger Footwell. A common problem with users is that as they replace the Sim Holder/Sim for either the Sim &/or Holder to fall down behind the carpet which is hard to retrieve unless you have small hands - be warned.
2. That small slot is NOT what you are/were thinking, the amount of times users post queries as to why their Sim will not fit.........In fact the slots real purpose is to act as a grill to hide a Sensor behind - I think either Temperature or Air Quality!