I should think it's quite likely, since JMB rented Stanway House for 12 summers from 1921 and he invited family and friends to stay. There is a mention in Nicola Beauman's biography of Cynthia Asquith that in the first year, some guests were getting on Barrie's nerves, including Jack's wife Gerry - according to one of Cynthia's letters, "Barrie's nerves regarding Gerry worse and worse, quite annoyed at finding her in my room". That's the only reference to Jack's visit though, and nothing about Peter. Bearing in mind both Jack and Peter were both adults and married by then, and therefore living quite separate lives, there were probably not regular visitors though.