Shortest distance from City of Westminster to Southampton Airport is 78.8 miles, shortest distance to Lydd Airport is 73.2 miles. According to the AA's mileage calculator.
SOU is eminently qualified then: London-Southampton
there was an old joke around Dublin airport that Ryaniar wanted to rename City of Derry Airport, Dublin North. I tend to agree re names of so called London Airports is Ams going to be London East!!!
Ha ha. Wasn't a joke when BOH became "London-West".