How to get your Three PUK code without ringing them up!
This works very well, I did it 2 hrs ago.
To do this, go to live chat on three.co.uk or three.ie.
Fill in the details (e.g. Phone number, name).
Ask the agent for your PUK code.
Follow the instructions he/she gives you.
The agent should give you your PUK and SIM card pin.
If this didn't work, tell me in the comments!!!