Air carrier Captain reported a missed approach during final due to aircraft on the landing runway. Flight returned for an uneventful landing.

Narrative

Arriving into ZZZ the aircraft in front of us missed their turn off and we were given a go around at roughly 30p feet. When my FO briefed the go around I added to it 'if it is a last minute (below 50 foot) go around I will stay off the radio. If it's a higher altitude please let me finish my radio call before beginning the go around process.' When ZZZ called the go around and while I was on the radio my FO pressed the go around button and began making call outs for go around; flaps 15; check thrust. None of the I heard though I know them so I did them after I got off the radio. I forgot we did not have auto throttles engaged and checked the thrust but did not set it to the green carrot. We had climbed a few hundred feet and I noticed the gear hadn't been called yet while checking thrust so I called positive rate. My FO then continued with that call out and asked for a heading. Around the time the flight director vertical command bars dropped off. I initiated the level change set clean maneuvering to get them back; this was roughly at 1100 feet. We proceeded to accelerate; given another heading and off to departure. It was at this point we realized our climb was less than desired and bumped the thrust up. Seeing them set roughly 8 n1 below the carrot before we advanced them to the carrots. The rest of the missed and return to land was uneventful.