I believe anyone who searches after truth is a Hindu. There is One and only God and One Truth. The very first book of Hindus named Rig Veda proclaim, “Ekam Sat, Viprah Bahudha Vadanti”. (There is only one truth; only men describe it in different ways). So a Jew or a Christian or a Moslem who is in search after truth is automatically a Hindu. There are about 1.5m Hindus in UK [including Jains, Buddhists & Sikhs]
As I replied on BBC The Big Question 23 August 2009 “Should religions tout for business?” & “Was Mother Teresa wrong in converting Hindus just before their death?” – inclusivity and non-proselytisation are mutually inter-dependent and respective. There is no need for a Hindu to convert anyone nor is it necessary for him to be converted.