I am sure this is the same mother and cub as last week even though the cub appears much bigger this time. The difference must be due to the distortion of perspective by the (relatively) wide angle lens on the trail camera, as well as the relative positions of the two otters. This was last week
and this is now.
On the next occasion I had a second camera in a ditch about 100m away and it picked up the same otter four minutes later. Again the otter was on it own.
On the latest recording the otter was again with the cub. She led it through the culvert and jumped up the gate but again the cub couldn't get up. Mother reached over and grabbed it but unfortunately the first time she got it by the nose or the whiskers which looks and sounds very painful. The second grab was more successful and she hauled it up by the scruff of its neck. On this recording the cub looks almost as big as its mother.
Since then I have put in a plank to act as a ramp so it will be interesting to see if they use it.