I use Graze on 90 too, but remember to keep horses off till it has died down and rotted well away. I prefer to rag fork them out, that way you don't have to keep the horses off.
I've only tried Roundup and Barrier H. Of these, the Roundup was too difficult to keep to just the ragwort and killed off the whole patch. The Barrier H did a really good job.
I've got some selective herbicide as well and will spray pretty much the whole field during the spring, so hopefully that will kill some off too
I had my field sprayed but it didn't work -don't know what they used. I wasn't charged in the end.
I have a ragfork & use it, but I find that any tiny bits of root left behind just grow back again. Also, the problem became too large for just me & one ragfork!
Am going to have it sprayed again this year by someone else. I'm told the best time to do it is in April when actively growing.
I have loads of problem with it, have had lots of sheep on last couple of years early and that has made a big difference as it didn't get chance to flower as much. Was planning to spray next month with headland polo in the hope that I can use the field in the summer.
I found this site the other day web page has anyone come across it and know if it works? sounds like a good idea but no idea of cost.