Re Nicholas49
And if I may add a cheeky sub-question (perhaps related?): when does a missed approach become a go-around? Again, is it a certain stage of the approach?"
Without too much technicality:
A missed approach is an instrument approach procedure covering the track/altitude the aircraft flies after the go around and is initiated at the missed approach point if visual reference is not obtained.
E.g. Track 160 climb to 4000 or as directed bt ATC.
The aircraft then goes around following the both aircraft's (power, climb, flaps, undercarriage) requirements and the instrument chart/ATC instructions. On large aircraft the go around is initiated by the TOGA (take off/go around) button on the throttle lever.
Go around is also the phrase used by ATC to instruct an aircraft to discontinue the approach and may be used at any time until wheels are on the deck. A go around can be given very late by ATC and could be for numerous reasons: Preceding aircraft slow to roll or vacate, rejected takeoff, FOD, animals, runway incursion.
ATC should give the instruction before the landing crosses the threshold.