You know how you can sometimes ignore a problem and it will do the decent thing and go away? That was the tactic we employed with the last, very stubborn, cotoneaster root. It worked for a while as we crumbled compost bought from the local Recycling Centre and sowed seeds until we were all PollyAnna'd out.
But, one day, as we discussed the planting plan for our future 'orchard' (by the way, how many fruit trees do you need to be worthy of that label?), we knew we could put off the problem no longer. Happily, Geordie Frank, one of our resident pensioners (say it quietly) wandered past and picked up the challenge. Within moments he was back with his work boots on and shovel… er, pickaxe… er, saw in hand. My,my, the way he tackled that root. You had to see it, it was impressive. And all for a cup of tea and chat with the ladies (I think we can call ourselves that).
(And, by the way Frank, entre nous, you don't look a day over ... oops, no, sorry, promised I wouldn't.)