This Cat 3 CP is to implement the following new metering guidance documents created to support Parties with understanding systems and processes updated for the new Market-wide Half Hourly Settlement (MHHS) arrangements: Sharing Metering Asset Data – MHHS Guidance Document Change of Market Segment – MHHS Guidance Document MOA Appointment – MHHS Guidance Document These documents were consulted on in June and July 2025 and were approved by the Metering Expert Panel to be implemented as Category 3 documents under their responsibility at the July and August MEP meetings.