Break from the birds - Who's home is this?

While walking through a large Bluebell woodland on the edge of my local patch I noticed a hole in the base of a tree trunk and outside the hole were droppings in a neat pile and these may hold the clue to who is living there.

 My first visit

 

A few days later and there was a Wood head and part of the body outside the hole

 Polecat poo taken a few years ago

The Bluebell woodland is bordered by lots of a Railway, canals, farmland, rivers and has a marshy pond area so it's quite a varied habitat which makes my decision on what is living there. Due to the size of the hole I was left with a few options Mink, Weasel, Polecat or Stoat. The droppings size and contents narrowed it down to 2 options as the droppings were in a tidy pile outside of the hole rather than where the animal sleeps or has young and I have seen this behavior before when tracking/researching Polecats and my other culprit is Mink. The droppings contained fur, fish bones/scales and feathers which is both of the animals main diets but the strange thing is there was no strong odor in the hole or coming from the fresh or old droppings. I have come to the decision that the only way to find out who's living there is to setup in a hide and wait for the culprit to return.
I will update as and when I get some results in my observations from the woodland. 
I have named Otter wood due to the location being one of my best places for a possible Otter encounter which can be seen in older posts on this blog.

Thanks for visiting 

Mike

PS-Hopefully it's a Polecat as I have never seen a pure wild one on my local patch!!!