I dont think we can compare SEN anymore with SOU.
SEN now have 3 x FR 737-800's and 4 or more EZY A320's based there, plus other daily Airbus's coming in with Wizz starting up, & Air Malta etc -
Stuff that SOU can only ever dream of...
Social media reports vocal objections at the recent roadshow.
It maybe now much harder to get PP through due to the increase in Climate, Noise, and Eco objections, especially after recent events with the climate warriors in London and at LCY.
SOU had opportunities years ago to get this PP through and they stalled it - That ship has now well and truly sailed, and it will likely be an uphill battle to convince planners and locals alike the benefits of the airport expansion now.
God help us now if the LHR 3rd runway starts any serious planning....
And LTN has had night flights in and out since the days of Autair BAC 1-11's going off at 02.00 hours, 3 of them at a time....LOL