Found this in the end.
https://www.acl-uk.org/wp-content/up...EMBER-2019.pdf
First paragraph mentions a movement cap for the winter so it looks like it has started.
Seasonal Movement Cap
A seasonal limit of 39,129 commercial passenger movements will apply
For the summer the airport has put in a seat capacity cap instead of a movement cap.
https://www.acl-uk.org/wp-content/up...eclaration.pdf
Seasonal PATM Seat Limit
A total limit of 12,880,000 seats will apply across all Passenger Air Transport Movements coordinated in the S20 season.
If all those seats are reserved for the summer then Luton will not get any Euro football charters.
Also has the airport given each airline a quota dependent on their last years figures? Could seats be traded?
Southend will do well out of these restrictions as airlines go down the pecking order. Could also explain why Wizz opened a base on the Essex coast.