I’d suggest consulting your agronomist (Lewis) and maybe using Kyleo,roundup and 2-4d to really hammer the established docks.Has Noone come along to comment yet..
Spray it Lewis, then spread a bit of lime to counteract the anti germination acidity caused in the rotting old turf process.
Then drill .A simtech ?
Or spray right after drilling if no lime to spread and that will hold off the bad effects of the acid problem....
Also You might have to live with a wide row spacing ....depending
....