Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
Gifts to charities are, in general terms, exempt from UK taxation. Although the seven year rule on gifts, where such gifts are added back to the donor's estate for Inheritance Tax (IHT) purposes, as they are charitable they will not count against the 325K tax free exemption. When all the chips are down if the estate is willed 10% or more to charity then the rate of IHT drops from 40% to 36%. That is the only tax benefit these kind donations will receive.
I am so sorry to have to rain on your parade.