Where are our Red Grouse?

Last autumn it was estimated that there were about 30 breeding pairs of Red Grouse on Beeley and East Moors. The grouse showed well with the usual bouts of early morning calling and lekking through to May but since the end of May I have only seen one party of 5 birds in August which were on East Moor. I've discussed this several times with Ken Smith, who has many more hours around the moors than I have but he has only come across 2 or 3 birds on three occasions over the same period plus an odd call or two.
If 30 pairs had been moderately successful they could have raised 120 young increasing the autumn population to around 200.
Populations of Red Grouse are known to fluctuate on about a 6 yearly cycle and so it may just be that we are at the bottom of the cycle but what has happened to the adults?
James was on Bamford Edge a couple of days ago, which is only about 10 miles to the NW, as the grouse flies. He estimated that he saw well over 40 birds in a couple of hours so clearly that population is doing better than ours. He took this photo of a fine male.

Red Grouse - male