Hi from Auckland, New Zealand! My name is Lynn and one of my late mother's treasured possessions was a delightful letter written to her by her cousin, Ian (Teddy) Morison, from Park Hall, Bixter, Shetland in 1939. Googling the address has led me to your conversation, somewhat belatedly. Teddy was there on school hols and describes the many activities they participated in. He also illustrated the letter with his own sketches. His father Robert had a medical and a divinity degree, so perhaps he was a colleague of the Dr Bowie who later owned Park Hall.
This doesn't add much to your knowledge of Park Hall, Bixter, but it was such a surprise to recognise the address and see the rather forlorn photos of it today.
I hope your project was successful.
Kia ora, Lynn Spray