Expressflight
If the runway is modified, ie a northern extension, due to its width it will stay a Code 3 runway which will dictate a maximum TODA 1799. Cannot imagine that CAA will permit continuance of the present inherited TODA.
One spin off from a northern runway extension would be an improved obstacle environment after departure on RWY 20, and the possibility that the offset Type A Chart could be used by a greater number of aircraft. When I last looked at this problem, when the E145s arrived, obstacles (ie trees) in Marhill Copse were too close to the end of the runway to permit a turn to be made to take advantage of the improvements to be gained by using the offset Type A chart.
A TODA of 1799 works for EZY at SEN, and SOU already has better LDAs than SEN. That only leaves finding somewhere to park two or three A320s and a E195!