The answer is, no you don't necessarily need a choir, simply because many British church weddings feature a mix of live and recorded music.
Traditionally, a choir performs two main functions in a regular (non-Mass) wedding service; to sing an anthem or two, and to lead the hymns. (An anthem is a piece of church music often sung in 4 part harmony.) Singing at various other points in the service, such as the signing of the register, entrance and exits, are purely optional.
So, it is perfectly possible to have a soloist lead the hymn singing - don't worry, as opera singers, our trained singers will definitely be heard! You can also ask your soloist to sing a solo or two as your sign the register, or play your own recording if you wish.
At Singers4Weddings, we usually come as two soloists so we provide a little more vocal range for the hymns, and we can sing a duet or two at the signing of the register, which is a bit more interesting for the guests while you're both busy!
Please bear in mind that most smaller church choirs draw their members from their local population, most (if not all) of whom will be amateur singers. Unlike the church or cathedral choirs you hear on tv, there may only be a few people available and their sound may not be as large as you would expect. As professional opera singers, much of our training is in making a beautiful noise travel a long way, so we can be heard and enjoyed even in large spaces.