Ah, further to my post above, I’ve just found this article that gives a bit more information…http://www.bristolpost.co.uk/Easyjet-passengers-locked-corridor-plane-leaves/story-19901080-detail/story.html

It appears that the group of 29 passengers got stuck in a stairwell as the security doors closed on them preventing them from boarding.

If the staff who worked the departure gate were missing 29 passengers prior to closing the aircraft door you would have thought that they would have at least questioned the possible location of such a large number of people and/or possibly sent an agent to check the areas between the plane and the gate to see if they were around?

Based on this, I believe that their baggage should have been offloaded too. I can imagine some difficult questions being asked of the staff in Malaga because EasyJet will now have incurred additional costs due to them having to pay out for the transport for the people who went to Gatwick and the accomdation for those that stayed the night in Malaga. Plus, I suspect the customers who stayed will have been re-booked at no extra cost so they will have also lost out on any potential revenue from not being able to sell those seats to other passengers that might have wanted to fly at the last minute.