Rachel sounds like an American actress trying to speak Queen's English, but is supposed to be from east London where the predominant dialect is cockney. Did anyone on the set ever see "My Fair Lady"? Couldn't they have at least imported someone or found a better dialect coach? There are British programmes that one can watch to study the dialect like "Eastenders."
John wouldn't know how to play the guitar although he would know about music. Guitar, like painting in a previous episode about art, would take practice and time to develop the skill to play. All the genius in the world wouldn't make a good guitar player or painter unless they practiced.
I still can't figure out if that crease behind John's left ear (his right) is a scar or what. He's kind of cute, handsome, and yet a bit oddly shaped like someone whacked him on the top of his head and it was driven permanently into his neck. Nice mouth and eyes though.