I had seen these flights a few months back as well. But since then they seem to have disappeared. The mayfly isn't always that up-to-date.
As for GSM, they are having enough problems at the moment, it doesn't seem logical for them to start up in CWL as they are only well known in Scotland. Apparently their MAN long haul flights havent even been that succesful. It would be strange to start CWL during winter, or even next summer as we are so far south, risky waters for them, when they could concentrate on whats a very successful short haul program in Scotland.