What is your goal? To hear or to see? If you want to see you've no chance based on a quick pop in, especially at a site that doesn't afford views of these birds because of its scale and the likely distance of birds from paths.
You are better waiting to hear about specific birds in more accessible barley fields - they usually are recorded at some point during the summer either from South Yorkshire, or Redcar area, or if you are not bothered about a couinty tick then north Notts. or Norfolk. You might be best waiting for the July influx - they seem to "show better" than earlier birds.
It took me a full week of trying last year before I eventually saw a bird that was calling in barley just yards from the road.
You could listen at Wheldrake or Bubwith area.
I'm trying to save you a wasted journey for what in my opinion is the hardest bird in Britain to see. You need to give it time and then expect to fail.
