Charitable Trusts like all trusts are basically ways of sheltering organisations from tax, and religions are one a number of groups within charitable law accorded charitable trust status, and it is a rebuttable presumption that they therefore perform charitable acts. Until quite recently the Charities Commission has been relatively inactive in investigating a religious group once it registers as such, this seems to be changing a little. It is though a religious and political minefield, so do not expect rapid movement in this direction.
That being said, as most of us know the wts do very little, if any, works that can in any way, shape or form that could be construed to be charitable. The wts is vulnerable in this area in The UK. We all know that the reason they claim trust status is to lower their taxes and reclaim them too.
David