Got a new phone on T-Mobile and wanted to give the old one to the missus. Shes on Orange so the phone was sim locked. Looked on the web for various rooting/unlocking options and they all looked a pain.
I also went to the site from Giff Gaff and they offered a special price. Filled in the details on Christmas Day and had the code in about 10 minutes.
Excellent service, no faff with software and no firmware issue.
I'll use them again if I need to