Otter actually sounds more likely if the creature was 'running' or 'bounding'. Coypus sort of hop when they're moving quickly.
Max has nailed it (I think)
Although smaller than the Otter in the clip, (and after much google research) I now believe that what I saw were 2 Otter pups.
Not long after my sighting I was chatting with one of my neighbours who told me that he saw 2 otters playing in the little stream at the bottom of my garden - I didn’t put 2 & 2 together at the time (Silly me)
Thanks for all your replies, but Max takes the Cigar on this occasion.