As for Wizz, I read an article where Chief Operating Officer Owain Jones was talking about the new LTN base, saying: "the speed of its network growth meant the opportunity to gain some additional capacity in the restricted London market was too good to refuse and will also lead to further operational efficiencies."
"Further operational efficiencies." That means operating out of one airport which offers total feasibility to move aircraft and crews around when needed say for maintenance.
“We thought we should take advantage of the new overnight stand, and also the opportunity to simplify some of our operations in and out of London.”
Sounds broadly in line with what Glyn Jones has talked about when promoting SEN, so I wouldn't be surprised if Wizz were interested. They seem keen to expand their London flights.
There is enough capacity coming on line at Luton over the next couple of years to keep Wizz happy I would have thought with extra stands and an increase in slots due to taxiway improvements.
I have learned never to say never but a SEN operation seems unlikely as the report mentions about "the opportunity to simplify some of our operations in and out of London.” You don't do that by splitting your operation.