Whether or not it's completely down to Brexit we'll never know. It may never have worked out anyway.
AFAIK it's 6x weekly in October, then 5x weekly until Jan. Returns 5x weekly in March and back to 6x weekly in May. Still doesn't appear to return to daily though, even July is still 6x weekly.
No 767 next year either, nearly every European city was on the 767 this year so it seems to very much be a one off season.