From what I’ve seen when a British newspaper says “Asian” in an article about Muslims they usually mean Pakistan and Afghanistan, not Indonesia and Myanmar.
Constant misunderstandings about the different connotations of the term 'Asian' in Britain and the US.
In current editions of the Oxford English Dictionary, the definition is as follows:
In Britain 'Asian' is used to refer to people who come from (or whose parents came from) the Indian subcontinent, while in North America it is used to refer to people from the Far East.
N.B.no religion is necessarily implied when the term is used...in Britain it's as often used of Hindus or Sikhs as Muslims.