"Recliner" wrote

happening with Greater London, perhaps because so much of so many
historic counties came together that no group dominated.

The strange anomaly is Middlesex, which has been entirely absorbed into
Greater London, but whose name persists in postal addresses in some
boroughs, but not others.

"entirely absorbed"

Not so, thus Surrey got Sunbury, Shepperton, Ashford and Staines;
Hertfordshire got Potters Bar and in further changes Berkshire got Poyle.

For extra credit, point out the bit of Surrey that was north of the Thames
before these changes.


--
Mike D