My father, born in Amsterdam in 1910, and deceased in 1999, visited also the jamboree. As the person you are looking for might still be alive, I do not want to see his data here. With an address of before 1939 we might find him in our census like bevolkingsregister.
Please give me an email address where I can reach you or use j.m.brul@gmail.com to send the data.
Some costs migth be involved to get an official record about him. He might be in the phonebook. Hopefully is his familyname not something like Smith, de Vries or Jansen. I presume that Dik is his first name