Very similar to my experiences. I have tried to book stalking on Deeside for a number of years now, both stag and hinds, and rarely get to speak to someone who can actually take a booking and never get a call back from someone who can. 90% of my own stalking is roe, but i like to get a week or so at the stags, but in day or two blocks because of work commitments. I try to get a couple of days at the hinds at the beginning and end of the season.
I have now hooked up with 2 estates / outfitters, both further away from home in Aberdeen, but who can take my booking and can offer regular stalking, and book a trip for two of us every month or so in season. I think Deeside and Donside have fishing, grouse and week long bookings and are happy just to take this and are not interested in day or twos booking. This is certainly my experience.