From this response here https://community.giffgaff.com/t5/Help-Support/iPhone-locked-to-GiffGaff-HELP/m-p/20116965#M7237013 it seems like giffgaff agents can now request a phone which was not bought from giffgaff be network unlocked from O2...
"I (the giffgaff agent) have passed the following details to our unlocked team in order to have them carry this out for you. It can take up to 5 working days, but I appreciate your patience in this matter."
For the benefit of us helpers please can someone confirm whether this is now permanently the case or if this is a one off.
As far as I know the agents have always been able to request unlocks but only (until now) for phones bought from giffgaff that have arrived locked to O2.
It'll be interesting to see how this pans out because as well as the staff in NI and the WFH agents,Firstsource also employ some "offshore" agents and from the look of a couple of gramatical mistakes in the agents reply I'd say there's every chance that they're not a native english speaker so let's just hope for the OP's sake that there haven't been some wires crossed here.
It is possible the OP didn't mention it was originally purchased through CPW, and the agent has assumed it is a giffgaff purchased phone.
We'll have to see how it pans out.
It would seem logical for giffgaff staff to be able to use a backdoor process to be allowed to do the unlocking, since the locking is to O2's network and not to the O2 sales team.
Why should a customer have to pay £15 to O2 and waste an O2 SIM, when giffgaff could collect the fee? O2 gain nothing apart from the unlocking fee. Giffgaff may also be losing a customer to another UK network, or the customer may be wanting to use a local SIM when going abroad, and still keeping an active giffgaff SIM for when they return. (They won't be returning to O2, I'm sure.)
I guess someone will have already suggested this in Labs. (Probably lots of times...)
As I thought - https://labs.giffgaff.com/idea/16704238
Edited to fix an @ mention which hadn't worked due to the "Too many searches" in the system.
I had been thinking of posting this as an idea in Labs for quite a while but saw @timwilliams25 similar idea and decided to give some support to that. It's a shame it's not had much support previously, and although the other comments are valid points, I think there is a missed opportunity to solve this unfortunate situation people often find themselves in with 'self-locking' SIM free iPhones.
If O2 can unlock SIM free iPhones for £15 why can't Giffgaff do the same?