I have been to regency with my RS and the missus Kombi for an identity check and there was some helpful guys there and I got through no probs.
Just make sure the car is clean and tidy, that your lights are working and there is not excessive oil everywhere or anything that screams, defect me for bald tyres, they have the option to send you over the pits if they dont like what they see. If your windows are tinted, they will do a light test on them and potentially send you out into the car park to remove any tint off the drivers and front passenger windows if they are too dark.
Don't know if you did it when you brought it, but double check that your chassis no matches the plate and is easily readable and that the engine no matches the rego and again is easily readable.
As an observer while waiting, it was funny seeing how all the guys who seemed to have an attitude got the same back from the inspectors, I suppose that is karma working.