Think it definitely is rabbits. The holes are about an inch to 1 1/2 inches in diameter. Sounds like it might be a rabbit burrow in the bed! Oh my. I have just been on the allotment. Dug out the holes a little and put stones in them and a brick in one, but doubt if this will deter them. We had an allotment cat last year who love eating baby bunnies but no sign of her this year so far.
Any suggestions for rabbit deterrents greatly appreciated. I do have a fence with mesh dug in 1 foot and half deep, but they can still get in the back fence near the road, I think and that is not replaceable.