Author: Alan, 5B4AHJ

Applications to ARRL to make UK Sovereign Base Areas in Cyprus were initially rejected. For example, the following is from RSGB Bulletin July 1962::

Following the announcement by ARRL that the ARRL Awards Committee had voted 6 to 1 to accept the DXAC recommendation that the UK Sovereign Base Areas in Cyprus should be added to the DXCC list, the following was published in RSGB DX News Sheet #1151, dated 1985-01-22. 

"ZC4  The ARRL News Release on ZC4 says: "Any credit submissions as a result of this action will not be accepted until June 1, 1985, and will be handled in the following manner: 
Credits for ZC4 contacts made before August 16, 1960, will continue to be credited to the Cyprus listing.
All 5B4 credits count for Cyprus.
All ZC4 contacts made after  the 1960 date were not necessarily with stations operating within the Sovereign Base Areas.
Cards that indicate operation from within the Bases will be so credited.
The  DXCC Desk will make good faith effort to ascertain the location of ZC4 stations where the location is not clearly indicated...
The militarybases are Akrotiri and Dhekelia."

1960-08-16 was the date that Cyprus became an independent republic.

Stations in the Republic of Cyprus continued to use their ZC4 calls until they received their 5B4 call on 1962-07-01. Thus, in the period 1960-08-16 until 1962-06-30, the ZC4 prefix was used from the Republic of Cyprus and from  the Sovereign Base Areas.

To complicate matters, SBA stations also switched to the 5B4 prefix on 1962-07-01, but reverted to the ZC4 prefix on 1964-09-17, see the "Related article" listed at the end of this article for further information. Thus, in the period 1962-07-01 until 1964-09-17, both SBA and Republic of Cyprus stations used the 5B4 prefix, and all stations counted for Cyprus, due to the statement in the ARRL News Release above "All 5B4 credits count for Cyprus".

In an attempt to determine which ZC4 stations would count for British Sovereign Bases in Cyprus, RSGB DXNS #1152, dated 1985-01-29, lists ZC4 stations which were  expected to count (based on QTH information from QSL cards), and the following, which were not expected to count:
ZC4CI  Famagusta - however some stations in Ayios Nikolaos, which lies very close to Famagusta, stated their QTH as Famagusta on their QSL cards.
ZC4CN Famagusta - as above
ZC4MO Mount Olympus - definitely counts as Cyprus, not British SBAs on Cyprus
ZC4RS Limassol - the nearest city to WSBA (very close)
ZC4SS Famagusta - known to be within ESBA - see below

However, DXNS #1153, dated 1985-02-05, subsequently lists ZC4CI, ZC4CN & ZC4SS as expected to qualify. ZC4CW and ZC4YC, who give their QTH as Larnaca, the nearest city to Dhekalia, were also expected to qualify, as they were actually in Dhekelia.

However, DXNS #1153, dated 1985-02-05, reports the following:
"A DXNS correspondent, who was active as a ZC4, reports that since 1960, all ZC4 licences have been issued by the Joint Signals Board and are subject to the rules, regulations and frequent inspection by that body. There is no question at all that all operations by ZC4s were and are from within either the two Sovereign Base Areas or from within smaller areas administered by the SBAs, No ZC4 callsign has been used from Cyprus territory and no Cypriot national has used a ZC4 call other than from within SBA administered territory."

Given that 5B4 licences were not issued before July, 1962, and that the ZC4 prefix was used for stations in both the Republic of Cyprus and UK Sovereign Base Areas from independence until 1962-06-30, the above statement is clearly incorrect. 
From 1964-09-17, all active ZC4 callsigns were QRV from within the two Sovereign Base Areas, or from the British military station on Mount Olympus (ZC4MO). Thus, since 1964-09-17, only ZC4MOZC4ER count for Cyprus.
RSGB DX News Sheet