One of the problems is that the only
published procedure for a standard overhead join depicts the aircraft approaching from the live side of the airfield. Exactly what the sequence of events should be if approaching from the dead side is undefined.
For example, should such a joiner cross the centreline to the live side while still 1000 ft above circuit height, before returning to the deadside in a left hand turn? Or is it acceptable to descend from to circuit height remaining on the deadside? In which case what's the difference from a crosswind join?