I think the context of procedural flight plan actually was in regards to our display, a procedural track is displayed basically where the system thinks the aircraft would be based on its ETD and TAS, rather then a return based on our radar or your transponder.
Procedural airspace basically refers to no radar, so the controllers use different standards to separate aircraft (rather then 5 or 3 miles). All class D is procedural, although they may have some radar coverage they don't use it for separation.
"BN Approach" also includes a sector that looks after class G airspace under approaches airspace, they use Brisbane Centre as their call sign (used to be Brisbane Radar), these are the guys you call to request clearance.