Well, never mind, since you've had them done already, but I was going to say there's a website IDphotos 4 you (I think that's it) you just take your own photos and upload them to their site, and then download the correct size you need and have them printed at Boots or Tesco or wherever near you that does prints.
Also, the US Embassy has a photo booth there inside; I saw it when I got my kids' passports renewed.