we are travelling to London and we'll be there for 2 days. what can one do in two days? aside form the Effiel tower what else can be seen. We arrive on the 19th and depart on the 21st. is it recommended to get the london pass and the hop on and hop off tour bus or just one or the other. Also I read about many afternoon tea but which is the best one, the one that gives you that experience of a true AFTERNOON TEA TIME. please advise.