A provisional improvement notice, or notice given by an inspector under section 63(3)(b), is not invalid merely because of—
(a) a formal defect or irregularity in the notice unless the defect or irregularity causes or is likely to cause substantial injustice; or
(b) a failure to use the correct name of the person to whom the notice is issued if the notice sufficiently identifies the person and is issued to the person in accordance with section 64.