rowan wrote:
If you have the patience and spare space just cover the ground in black
plastic sheet. It will take probably 12 months. I have used this
effectively on large areas badly infested after trying most things. I
have also loaded the surface with fresh farmyard manure before puttng
down the plastic.( 300 + mm. deep!) Got rid of couch grass, manured
ground and no space taken by composting. Three jobs in one!

I have never found plastic sheeting effective for getting rid of twitch. It
just sits there patiently under the surface and waits. Apparetly it is more
patient than I am.