Prunella/Clover weedkiller

Never come across Selfheal before. I started my battle with it on my newly inherited lawns 3 weeks ago with Evergreen 4 in 1. This has sproadically killed some of it but its gets itself wormed underneath the thatch and lives on there. Probably would have been more effective to scarify first. Anyway, the ground is damp and its quite theraputic getting down on hands and knees, raking selectively and pulling it out by hand. The roots come up easily. The weeds that are dead are like blackened wirey burnt heather and will only add to the thatch if not removed. Any stubborn bits get a sharp stab with a trowl to shift them. I feel im winning and if anything survives the winter and pops up next year it will get the scarify treatment before agent orange is sent for again!