Is there a law that says that there must be a Bible in every Church?

The Church of England is regulated by the law of the land including Measures of Parliament.

The Church also has its own rules, called Canons.

The Canons are supposed to be binding on its clergy who declare that they will uphold them.

Canon F9:

In every church and chapel there shall be provided for the use of the minister a Bible, including the Apocrypha, and a Book of Common Prayer, both of large size; a convenient Bible to be kept in the pulpit for the use of the preacher; and a service book, together with a cushion or desk, for use at the communion table.

Therefore, the expectation is that every Chuch should provide two Bibles one for the use of the minister and one for congregational reading.

The one provided for the minister is to include the Apocrypha because the CofE lectionaries include optional readings from this and because it has value "as an example of life and manners" (Article 6)