Likewise, I am with BOAC - but maybe from a more modern perspective (sorry!)
A regular instrument approach is a safe and happy place to be, because as pilots we can use two or more independent nav aids to confirm our position and path.
A circling approach in the 320 is also two sets of independent references that tie together to confirm our position and path:
1. You fly at F speed, break right for 30s level just above minima, turn left to track downwind, start timing abeam the threshold (for a pre-calculated height/wind corrected time), turn left (disconnect the AP) and descend. Do this and you'll be in roughly the right place.
2. You become visual with the runway and break off, you remain visual with the airport on downwind, you are visual with the threshold when you start the watch and your are visual with the threshold as you descend and turn towards it.
They are the two independent systems. One always cross references with the other - just like 2 nav aids. Even though either system will get you there, if you lose one - or lose the cross-check between the two, then that's your clue that it has gone wrong and you go around and think again.
Simple, cross-referenced and safe. Even a 200 hour cadet can do it.
