Grazon gets rid of nettles a treat .
Cut them down , rake off the cut nettles for the liquid feed . Don't use the compost heap asthey aren't usually killed in it if there are any seeds there .
When the regrowth is 3 inches tall zap them with the correct mix of grazon and bob's you uncle no more nettles in that area. If you rotavate the area you may well need re treat the new germination of nettle seeds that have lain dormant for many years in the soils
One good thing though is that if you can grow nettles you can grow almost all UK veg crops as the pH is ideal in most cases.