I must say I think it is a bit much that CHC have registered their Sumburgh S-92 G-CGOC (Coast Guard Oscar Charlie). They are clearly trying to cash in on the good reputation that the last Coast guard Oscar Charlie (G-BDOC) had in Shetland for the last couple of decades.
Doesn't make any difference now because all UK CG S92 helicopter callsigns will be: -
Coastguard 100 - Stornoway Duty
Coastguard 101 - Stornoway Standby
Coastguard 102 - Sumburgh Duty
Coastguard 103 - Sumburgh Standby
Coastguard 104 - Lee Duty
etc etc..