And only religious buildings open to the public (regardless of the beliefs of the member of the public) are exempt from business rates. Any places of worship that are closed to the general public are not exempt from business rates.
Again you are wrong.
To be completely exempt from business rates a building need only be registered as a place of worship under The Places of Worship Registration Act 1855. That doesn't mean the place must be open to the general public in the sense that the public can visit when they wish (within reason) for a variety of purposes. No all it means is that any act of worship cannot be theoretically restricted to members of that religion. It allows a building to be locked for virtually the whole week and only unlocked when worship is taking place, when of course general members of the public who aren't adherents of that religion are unlikely to feel they can visit.
And these buildings don't even exist on the Value Agency Office's database of buildings so it isn't really that they are exempt, they don't even exist as far as the ratings system is concerned. So as the VOA has no visibility of the premised how on earth would it know to what extent the building is available to be used by the general public.
Yet, of course, all other places that may be generally open to the public to use for a variety of purposes - e.g. libraries, museums, community centres, covered public realm spaces do not get the same exemption - typically even if run by a charity then they'd still pay 20% business rates.
And it gets worse when a religious building has, for example, a cafe run as a commercial venture - as the whole building doesn't exist as far as the VOA is concerned then they pay zero business rates on that cafe space. And for a charity that may have a cafe (e.g. a museum) that space is typically considered to be 'commercial' and therefore full business rates are paid.
So as a real example - where I live there I can think of three cafes within perhaps one minutes walk of each other (all are rather nice by the way):
1. An independent cafe - pays full business rates.
2. A cafe in the foyer of a local museum - the museum itself as a charity gets 80% business rates relief - the cafe area is subject to full business rates.
3. A cafe in the foyer of a baptist church - as the whole building doesn't exist on the VOA list the cafe space is completely exempt from business rates.
While I can see an argument that example 1 might be different from 2 and 3, how on earth can it be right that the cafe in example 2 pays full business rates, while the cafe in example 3 pays nothing.