I recall discussion around this topic over 10 years ago when the publication of arrival statistics really started to bite. The larger the destination airport = the greater the padding. So it is 'faster' to go LGW-IOM than it is to return. Non story but the media have learnt that the airlines will rarely shout back. You can whip them a thousand times and, mostly, they just take it. So that makes them an easy target for any story.