As stated on the Southampton thread, Loganair are to resume their EDI-CWL service (5x weekly E145) from the 2nd of August. Will be 3x weekly during the winter.
With regards to the BA Cityflyer winter Southampton route. Its basically a positioning flight down to SOU to operate the Winter Ski flights (CMF I believe) and returns on Sunday. So the flights were put on sale to make a bit of extra money instead of positioning down empty.