(1) Anything done or omitted to be done before the commencement day by a trustee of a trust (as defined in section 3(1)) that would not have constituted a breach of trust had the Ambulance Services (Further Amendment) Act 1999 been enacted at the time at which the thing was done or omitted to be done is not to be regarded as constituting a breach of trust and the trustee is not liable for breach of trust on account of that act or omission