I'm afraid the map might not be working quite properly for me -- I'm not seeing a red arrow -- but I ran over to GoogleMaps because I wanted to double check. I'm certainly not moving cities at all, but an arc passing over Ipswitch and Felixtowe seems pretty natural -- they're avoiding London because they're trying to fly over as few large cities as possible.

I had a look at the map when I originally wrote it (to find what cities they would fly over) and don't really have an issue with the geography. I've done London to Sheffield by car before and it doesn't even take a full day; the distance from Cambridge going southeast isn't nearly as far as that, and they're traveling at a fair clip.

Possibly the location of the Channel is more extended in my view than yours. I suppose more properly at that point it's the North Sea.