Unfortunately, it's all part and parcel of caring for nature and natural. If we truly love wildlife in our gardens we can't pick and choose what we want and what we dont. We lose a lot of our birds to Sparrowhawks. By encouraging the birds and small mammals by cultivating a wildlife friendly garden we must accept that we are also encouraging their preditors.
I can understand how you feel Polly but, although difficult, we shouldn't humanise the visitors to our garden. I am just as bad. The blackbird with the ragged tail who I had been nurturing all winter and who was feeding from my hand has now been missing for four days.
If we are to enable otters to survive then we have to help them.
They will only survive in gardens where the food is plentiful.