Bloody nettles

Well i'm back from Australia and having missed the snow whilst I was away i've managed to get down to the plot a couple of times over the weekend. I have carried on with the clearance and have decided that I really hate nettles, and not because they sting. On the surface you may have a small six inch (15cm) high nettle, but as soon as you start digging to get the root out you realise that it's a bit like an iceberg with only 10% of it above ground. The root systems attached to the nettles are huge. So i've now started to dig down a good two foot (60cm) to make sure I get it all out. I do however think I need to make a quick trip to the garden center and buy a large metal sieve so that i can put all the earth through it and get rid of every tiny piece of root, otherwise I can see it coming back pretty quickly.