Get the hex covers and then go to B&Q and get 4 round black plastic chair leg end caps. These are the ones that are for stopping your laminate floor getting scratched and they come in about 3 sizes and cost about £2 IIRC.
Like this>>>>>>>http://img.alibaba.com/photo/50506169/Leg_Tips_End_Caps.jpg At a guess the top left ones will be about right.
Like this>>>>>>>http://img.alibaba.com/photo/50506169/Leg_Tips_End_Caps.jpg At a guess the top left ones will be about right.