Gatwick was always the prize. Other London airports have partly benefited from a lack of slots south of the Thames so there might well be a knock on affect for other London airport if those slots are grabbed and aircraft are moved to fill those slots.
You can be sure Luton and Gatwick who had 13 Monarch based aircraft between them will be looking to fill their spare capacity making Southend’s quest for new airlines somewhat harder. This won’t be helped by the completion of Luton’s terminal expansion next year.