Definitely get rid of the ragwort for a start - lethal when in hay for sheep, horses etc. The grass here in the South West has not grown at any great rates this year and so you may struggle to get a good crop if you have only just taken your sheep off the grazing a few weeks ago. However, if you fertilize it, it is suprising how quickly it can come on, and you can cut hay as late as August or even later if necessary and the weather is ok for the process. I would also want to get rid of the thistles and any docks that might be there. It's very hard work keeping grassland in fine fettle, but producing your own hay is very satisfying.