[sprizzle]

I like this article as a thought experiment, but I think in practicality, it would probably be miserable to fly to-and-fro 4 days a week.

The main cost that was ommitted that would give us an idea whether the commute is worth it is the opportunity cost (http://en.wikipedia.org/wiki/Opportunity_cost). While it'd be difficult to estimate how much the author's time is worth, if we assume that he/she gets paid an hourly wage of W, and it takes H hours to commute to and from London, then the opportunity cost would be something like W x H. If that opportunity cost is greater than the 387€ in savings, then it would not be cheaper to commute from an economist's perspective.