For my stage 2 I flew down from Aberdeen via Manchester to Southampton the night before, stayed at a B&B 5 mins from CTC, and just walked up in morning! Then flew home via Manchester again. When I went down for my medical though my flight home was delayed so I got train from Southampton to Woking then the national express straight to T5 at Heathrow and flew from there, so that could be an option for you also!