if its a church of england church and your a british citizen I dont see why not.
Im pretty sure legally they have to marry you even if you dont turn up for X number of weeks. By integrating into state the church receives some benefits but it also has duties such as it has to carry out marriages funerals etc for british citizens.
It always confuses me how people can talk about the church as if its nothing to do with them. Its likely that most British citizens ancestors paid for the church either directly through the collection at mass or indirectly through taxation in the past. So frankly if my ancestors paid for the building why should nt I use it ?
And if your part of a community it is likely a building/temple/monument has always been used in the same area for marriages, deaths and other important events even before christianity.
One reason churchs are pretty is because they got the good spots first so why should nt they be used.
Christianity+Church has affected everyones life and the country so much that amazes me that people dont feel like it and its building belong to them anymore.