My High Def m2ts files are supposewd to be converted on import to MPEG-2 format but this is not happening.I cannot find any way of forcing this conversion.
I think there might be a checkbox to no longer offer the MPEG-2 conversion on AVCHD imports. If you ticked that before, the question won't come up again. You can reset this, though. Go into the MEP program settings and use the "Reactivate hint dialogs" button under the "System" tab or use the function in the "Help" menu to reset the entire program to its defaults. That should do the trick. On your next AVCHD import, the MPEG-2 conversion should be offered again.