When I set my Manhattan HDR-S to series link programs, it continues to record beyond the end of the program for up to 24hours and it can only be stopped by switching off the mains power, causes big problems when I want to watch and record other programs, anyone know how I can correct this?

This happens to me with the same box on occasion, like you I have to unplug to end the recording. Why it happens (apparently randomly) is another matter.