Question : How long do most people visit London?
Answer : Of course you're not most people, but if you were, you'd stay roughly six days.
Question : If your plans are flexible, have you considered changing your departure day?
Answer : The cheapest day to fly in April is Friday. Flexibility is paramount when booking travel plans in order to keep travel costs down.
Question : What day in the next four weeks has the best fares?
Answer : Since low prices are preferred, look at Apr 7th. As of Mar 27th, it's showing the cheapest ticket sales at $1,056. That is 32% below the average price for this route, so you can spend that extra cash on an adventure in London.
Question : Are you paying the cheapest or highest price for your ticket to London?
Answer : Ranging anywhere from $886 to $3,366, prices for SCL to LGW do fluctuate a lot more than most routes from Chile. Remember, you can save by booking further in advance.