Young Paul,
The majority of Pilots for easyjet are initialy streamed into LGW, as this is the largest base and subsequently requires a larger than normal workforce. Also alot of Pilots come here initialy before moving to there base of choice.
With the Madrid base opening up in 3 months time, a number of pilots from both LGW and STN shall no doubtly leave to live and work out there, and there will most likley be vacancies at both bases over that period.
With regards to the night stops, there are the odd few going, mostly to Madrid and if you wish you can inform rostering that you would like to be considered for night stops and they shall plan accordingly.
Hope to see you on the flight deck soon.