"after tower gives surprise instruction"
This was the reason for the original post. I couldn't understand why a simple instruction to turn away was beyond a pilots capability. I have now improved my understanding thanks to the "mostly" informative replies.
Apart from confusion over the back track it was a textbook circuit
Spey, it wasn't. At least 2 calls had to be repeated after no response, and after the initial go-around instruction he replied "GBB maintain centreline". As the go-around is to the deadside he would have been clear of the inbound. maintaining centreline means that no2 has nowhere to go in the event he breaks off. Therefore the ADC moves him out the way by turning to the North. He had 40 seconds from the initial go-around instruction and 30 seconds from the instruction to turn North before he turns.