bumble bee nest attack

this morning I came out and saw what looked like part of a cowpat on my front lawn. I do have problems with dog lovers but as there are no cows in this strood kent urban environment it clearly was something else. I have noticed little holes dug here and there in the front and back grassy areas before and wondered to what purpose?. Looking around my front lawn I notice erath exposed near the wooden fence of my property. taking a gander I see a mass of bumble bees moving about in the hole. I immediately suspected foxes as I know they frequent. As I am fond of bees and in particular bumblebees. I googled to find out about their nests and possible repairs. Unlike ants which are quick to repair damage these bees did not seem to be engaged in repair. I reckon an upturned earthenware pot over it might protect it from sun and rain but I have none. I put a piece of cardboard over the main mass which is pretty good to keep sun off and as the grass is very tall and tufty there, but of course though low to ground the wind will remove it. In many instances like this I guess it is best to do nothing as nature will take care of itself and what I do maybe detrimental. So I left it like that hopefully the main chambers of the bees is on the other side of the fence and the larvae espaced predation. Is the earthernware pot a good idea or should I let the next rains and weather sort it?. My back garden I let it riot and I'm sure I am the bane of my neighbours, yet it is always full of butterflies,hoverfliesand other flying insects which delight me. I am surprised by how many insects are attracted by bramble flowers which is probably why it is so successful a plant(aside from its thorns).