How do you tether your dogs on hard standing

We mostly stay on CLs and when on main sites try to get grass pitches. 

We have got screw in tethers so we can tether the dogs outside when the weather is nice and we are outside with them.

With winter approaching I anticipate being on hard standing more often. Are there any gadgets that let you tether a dog on hard standing. And if not, who do you do it?