It's just a basic chat about your flying carreer and in my case a CRM problem and how you will handle it (a Cpt who goes below the minimas and doesn't listen to you). Technical questions are very straight forward. About minimas on CAT I, II & III, balanced rwy,...
Sim at Gatwick is on a Hawker 700. SID, engine failure, holding, non precision approach (ndb). Again, you must show a good CRM...not only good flying.
These people are very friendly and relaxed. So no panic !!
Good Luck