This is a big rabbit hole! Investigating this has uncovered a number of different approaches and some strange anomalies. Hence, I have compiled some notes on what I have found. In summary, there are some good things, but the DMARC configuration is mostly misunderstood, has very poor governance, and shows little or no evidence of any auditing.
Centralised services
Education Scotland
Schools by Local Authority
Aberdeen
Aberdeenshire
Angus
Argyll and Bute
Clackmannanshire
Dumfries & Galloway
Dundee
East Ayrshire
East Dunbartonshire
East Lothian
East Renfrewshire
Edinburgh
Eileanan Siar
Falkirk
Fife
Glasgow
Highland
Inverclyde
Midlothian
Moray
North Ayrshire
North Lanarkshire
Orkney
Perth & Kinross
Renfrewshire
Scottish Borders
Shetland
South Ayrshire
South Lanarkshire
Stirling
West Dunbartonshire
West Lothian