The Ombudsman may, where section 52 applies, decline to investigate, or discontinue an investigation of, a complaint received -

(a) by the Ombudsman on or after the establishment day,

(b) by the Financial Services Ombudsman or the Pensions Ombudsman before the establishment day where a decision of the Financial Services Ombudsman or the Pensions Ombudsman, as the case may be, has not been made.