ENR 1.5-1.10.1 para. d. may not say it, but Note 1 at the bottom of section 1.7.3 does
The concept is as follows:
(1) The pilot maintains visual contact with the landing runway while the aircraft is circled at MDA to a position within the traffic pattern that intercepts a normal downwind, base or final approach.
If the MDA is above the downwind height, the aircraft maintains MDA and downwind spacing until it reaches a position from which it can descend at normal approach rates to join base…
(MDA can only be the circling MDA in this context)
If you have descended below circling MDA on a runway aligned approach, then any missed approach must be carried out to above a MSA