page 351,quote.
Despite all his efforts to publicly eliminate the trappings of British rule,de Valera continued to receive his commission from the Governor General, and whenever travelling outside the country, he requested a British passport so as to enjoy the protection of the Crown.
page 397 quote.
When travelling abroad, de Valera recognized the King of England as King of Ireland and signed his passport acknowledging the fact that he was a subject of the King seeking safe passage under the Crown.