jvc gz hd620b is the camera.
MTS converter is the converting program.
Log and capture doesn’t recognise the camera (USB only).
Mpeg stream didn’t seem to work at all.
It seems the issue may have been fps related. Converter defaulted to 30fps but it appears 25fps was required.
Interestingly iMovie imported, played and exported all files easily while fcp struggled. I actually exported the file from iMovie as a fcp pro res and that worked too. A round about way but seems to work