@bsprague, @ungermann - many thanks for your help.
I did some more research, and exiftool can extract 'datetimeoriginal' from the mts files as well - weirdly, however, it gives it as in the timezone utc-15:30 (I thought timezones ran -12 -> + 12?).
It seems that the clip info is really just for the camera and perhaps hdwriter.
However, all I really need is the date and time of capture. Thanks for the other tips e.g. for stitching the larger clips together, etc.