Greece was the only country where the B-534’s got by a direct export from Avia. But, they were not bought by the Greek Air Force, but by G. Koutarellis, a businessman, who bought two B-534’s of the second version with s/n 534.1001 and 534.1002. These were handed over to the HAF after a consecration ceremony on 18 August 1936.
Two Gloster Gladiators were bought in the same manner in 1938.
The Avias fate is hard to track as they were always listed as "Avias" together with the four BH-33’s, supplied from Yugoslavia a year earlier. They were probably used with them for fighter training purposes.
All six of the Avias of the two types was on strength of the HAF as late as the time of the Italian onslaught in 1940. As they were distributed to different combat units, they were probably only used as armed liaison machines.

Source:
Avia B-534 - Jirí Vraný, 1994