Earth excavations!

Hi 

I have had hedgehogs in my garden for several years and this year saw three together - one large and two smaller ones. A delight! My coal shed door is rotten at the bottom and a couple of months ago, before my coal delivery, a hedgehog started to next in there. I had to move it so built a little house nearby,  moved some of the dry leaves into it and left some outside. These were taken in over the next few days. I used a large bore ceramic pipe as a lead into the house. I borrowed a night camera and hedgehogs definitely went in and out of the house but I could not determine if they lived there! Very recently a growing pile of earth (much like a mole hill - but I have never had moles here and there do not seem to be any in the neighbourhood) has appeared at the back of the pipe which will now be partially, if not wholly, blocking the entrance/exit. Simultaneously, a 2" diameter hole has appeared in the lawn nearby - rats maybe? 
Does anyone have any ideas as to what is creating this earth pile and should I remove it?

Thanks