AVOID!
AVOID!! I wanted to unlock an old iphone to resell, and went to the EE site, which directed me to MobileUnlocked.com. I was initially charged £9.59, and thought well that must be the cost nowadays (had never paid before when I was with o2). It was supposed to be really quick, but had to wait 24 hours to be told to complete the unlocking I needed to pay another £24.99 - the unlock release fee. I asked them to send me a screenshot of where all the costs are listed, and of course they have never done so. I will now go directly to EE and flag up that is this is extortion, and I am not paying anything further than the £9.49 to 'establish that I was eligible' - I knew very well I was eligible. I believe you can also unlock via your iCloud - also no charge. They're not even a quick service if that's what you needed, and only use if you're happy to pay over £35 for this service, which you can get for free.
I've been asked to add details to this review, so I will repeat - what I asked was to see where on the site there was a clear outline of what I would be charged, rather than charging me initially, and then wanting to charge more for completing the process. I simply requested a screenshot of this information on the website which was not forthcoming