I see you're in the UK so this may or may not help you, but I just attended my God-daughter's naming ceremony a few days ago. We are very active in our Native American Church and this is where the ceremony was held. It was a beautiful statement of love from us (the community of people that love her) to GD (sometimes out of control 5yo). I think that regardless of your beliefs or lifestyle you can create something meaningful for dc by doing things that you think are important. We gave GD gifts and she gave some select gifts herself. We all said prayers and sang songs. Before the actual thing she and I had a long talk about what it means to have this ceremony and what getting this new name meant for her - basically that she is becoming a big girl and this new name is her big girl name, and that she shouldn't act like a baby anymore because she isn't a baby. We actually give the child a new name, we call it her indian name, which the medicine man picks. I'm not sure how he comes up with it, but her knew her very well, and the new name was very fitting to her. The godparents walk the child into the ceremony (we have it in a circle) and present her to the parents. The medicine man talks about how it is the responsibility of both the parents and the godparents, but also the whole community to raise this child well. After the naming, the godparents walk the child around the circle to present her to everyone attending and they all hug her and tell her they love her. Then everyone hugs everyone else and we have a big meal and all the kids play and have a party.
I hope you are able to create something that means a lot to you. The best advice I can give is don't have ceremony full of traditions that are meaningless to you...do something you love with the people you love - that is the most important part of having a special event for your child.