When I did mine (had been left for four years) I cut down all the brambles and left twelve inches sticking up, so that I knew where they were when it was time to dig up the roots, bought a new grubbing axe and leather gloves from Screw Fix and grubbed out the roots and had a big bonfire, lovely now, all planted up, the odd bramble that I did not get all out and begins to show I poison with brushwood killer, and dig up when dead just to make sure. you wouldn't think it's the same plot now. best of luck.
