I arranged one day last year, August 13th, 125 brace. The shoot was in Yorkshire and was arranged by Rob Peel and Lioncrest Sporting and Primoris Sporting, Matthew Finch.
Rob, formerly of Holland & Holland shooting school, was my loader and driver and arranged everything for me. He was great and things couldn't have been better.
Before shooting, I booked an afternoon at H&H's shooting grounds as I had never shot in England with double guns. This was a treat and I think its a good idea to have this instruction before heading to the grouse butt. Nathan Dudley was my instructor there and he is a very nice man and an excellent instructor.
Holland & Holland and Andrew Ambrose in London for stored my guns while I was in London and then later transported my guns their shooting grounds for me, they made gun logistics easy.
I would highly recommend the experience and the individuals who helped me and encourage you to go forward with your planning. Please PM me with any questions, if necessary.