Just a big up to a company I've used: www.goldfinger-rings.com/
They come to your house with their rings and handmake something beautiful for you. For me, they made a shaped wedding ring to go around my engagement ring and did an amazing job. They also don't take your engagment ring away to make the shaped ring. They did a complicated thing with paper to make a model of my engagement ring instead.
However, though their service sounds similar to Smooch Rings, they are give a much better service.
If anyone wants to have a look at what they made for me, PM. They are really resonable and hand deliver all their work.