Foxes scratching holes in our bowing green

These foxes probably sleep in rough land which is adjacent to the bowling green and they are progressively damaging the well kept green by digging a few holes each night and also removing the earth from any that has been repaired. I have no confidence in any repellant products on the market due to an experience I had years ago when they damaged my heather garden, but I am wondering if anyone has found a way to deter them. Following tips from other bowling greens I have acquired a large number of 2 litre pop bottles which I shall fill with water and hopefully that will frighten them off as they are apparently scared of seeing their reflection in the bottles. Using crushed moth balls is another suggestion, but I learn that they are now banned.