going to Bulgaria this Christmas (well, intending to), this is from 2 pages on their own gov website:
"Passengers permitted to travel from a Red Zone country
must present both a Vaccination Certificate or a Certificate of Recovery from COVID
AND a negative PCR test conducted within 72 hours of travel on entry. A negative antigen test
is not accepted for entry from Red Zone countries."
pretty clear, UK is Red Zone. Next page;
"NOTE FOR: Citizens ... arriving from a member state of the European Union, the European Economic Area, the Swiss Confederation and from the United Kingdom of Great Britain and the Northern Ireland or from a country listed in
Annex 4 of the Ordinance are allowed on the territory of the country upon presenting one of the following documents:
a negative result from a test conducted up to 72 hours before entering the country by the method of polymerase chain reaction for COVID-19 (PCR test), certified by a valid EU digital COVID certificate for testing
or
• a valid digital EU COVID-19 vaccination certificate,
or
• a valid digital EU COVID-19 recovery certificate,
or
•
an equivalent document containing the same data as the EU digital COVID-19 vaccination, recovery or testing certificate."
right. Choose which page to believe.