I've just returned to this thread, and yes it's got interesting. To quote the last post:
It seems to pretty clearly indicate that ATC using radar must clear you to a lower altitude to facilitate your descent within the circling area/5/7/10nm, and that the PIC must not descend below the last assigned altitude until within the circling area/5/7/10nm.
I agree completely, and while I'm happy to listen to and analyse all others' opinions, I still haven't read anything in law or published procedure that says I can, when arriving at a Class C aerodrome and cleared visual approach, descend below the
last assigned altitude until within the circling area (or the 5/7/10 rules if coming straight in). Seems to be quite a few people who are adamant you can descend on the DGA steps etc. when cleared visual approach in controlled airspace, below the last assigned altitude, while still outside the circling area. While I'm not saying this is plain wrong, my interpretation of the published procedures indicates that it's not correct.
Whether ATC has permitted it in the past is a whole other point in itself. But I don't see anything written down which says it's allowed.