Portugal
Whilst attending the Perse before Scouting F E Giles is quoted as having founded the Portuguese Boy Scout Movement.
Italy
The 17th Cambridge (Catholic) claimed a direct influence on Italian Scouting. A report of the Scout trip to the Vatican in 1926 recalls ‘it was Duchemin (ex 17th SM, a student there in 1916) who ensured the Italian scouts were allied to Imperial HQ and a photograph of the 17th was the model for the Italian uniform.’ Other histories of the start of Scouting in Italy do not relate these details, however, it is evident that several links to British Scouters influenced the early movement which stuttered into being. See report Feb 1926
Poland
The following Rover course was held during WW2

A special case but one that illustrates the numbers of Poles in Britain at that time and the interest in Scouting during a period when more immediate issues are abroad.
An entry in County records of 1963 states that Groups had to apply for permission for foreign Rovers to join British camps.