I'm with Robert on this. Pulling ragwort properly eliminates it over time. The following came from an article written by Dow AgroSciences and published this month
"Cutting or mowing ragwort is not recommended as this stimulates new growth from the base of the plant and leaves wilting biomass on the ground. These cuttings must be removed before the animals return.
"Digging put the plant, roots and all, in the spring when the soil is moist is a good option where infestations are light. It is a good idea to wear gloves as the toxins can affect humans
"If the ragwort is growing across the whole field, a blanket spray of Forefront will give very high levels of control. An alternative option is a mix of 2, 4-D and MCPA.
"All ragwort foliage must be removed or completely decayed before stock is allowed back onto treated fields"
When a big chemical company says to do it by hand it means there really isn't an easier way it can sell you. Forefront is said to be available for some reason only in Scotland and the South West.