For anybody who have not booked there holiday flights yet, it might be worth taking a look on the balkan holidays website.
Reason being, I booked our flights in Feb at a cost of £562 for 2 adults flying from Aberdeen to Bourgas on 18th June. I would now be able to get them for £368. Very frustrating and when i phoned Balkan i was told it will cost me £140 to cancel and rebook. I will have a saving of £54 in the long run.
Don't know if it's because of the departure airport and they are trying to get "bums in seats" , but certainly worth a look.