L337- we don't have such things as visual go-arounds in Europe- it's a US thing.
GSPOT- you're changing the question to suit your answer. The question was about 2 parallel runways as at LHR. You have no experience at airline ops at airports like LHR, so your answer is misleading.
I have had this situation at LHR several times over the years. Each time there has been the opportunity to switch over ILS to the new runway. So why would you fly a go-around on a runway you are no longer approaching? As I said, the likely reasons are: slow clearer ahead and other runway clear, opportunity to take off aeroplane on original runway and other runway clear, or other runway clear and you want to park near that side anyway. So if another aeroplane then gets cleared to go on your original runway, and then you decide to go around and turn across LHR and overfly your original runway that another aeroplane may be lifting off, then you are demented and need to be carted off. You have simply changed your approach to a different runway! Why on earth would you then fly a go around for a different runway? It's crazy! It is not a circling approach! Why try and make it one? This is the real world, not academic ATPL stuff, and an element of common sense is needed.
I do not believe ATC do this any more at LHR anyway. It is a procedure that is now frowned upon in airline ops I believe. It must make the flight recorder monitoring go crazy.