According to IMDb (which is usually accurate), Netflix currently only holds the streaming rights to the series for the USA, Japan and the Netherlands.
http://www.imdb.com/title/tt2442560/companycredits?ref_=tt_dt_co
A month ago the Independent mentioned "a UK release date yet to be confirmed"
http://www.independent.co.uk/arts-entertainment/tv/news/peaky-blinders-season-3-netflix-release-date-us-uk-cillian-murphy-a7013091.html
but that might just have been guesswork (assuming that Netflix would also buy the UK rights), rather than based on any actual knowledge of Netflix's intentions.