Taxation on sale of Charity property

If a Charity sells a property it owns, and the proceeds of the sale invested/ placed in a deposit account. And only the interest accrued used for Charitable purposes, would the monies received from the sale be taxable under CGT ?

No! Charities are not liable for CGT.

I thought they only avoided CHT if the monies were used to fulfil charitable objectives?

By definition, monies held by a charity on its own account are devoted to its charitable purposes - the condition would only really bite if the trustees used the funds incorrectly in a departure from their constitution . Investing the funds in qualifying investments (including a deposit account) to generate income which is expended on its charitable purposes is fine - the charity is not obliged to spend the proceeds immediately .