One single bathroom for e.g. King Edward in Asia (4)
I believe the answer is:
aloo
'e g king edward in asia' is the definition.
(Hindi word for potato)
'one single bathroom' is the wordplay.
'one single' becomes 'a'.
'bathroom' becomes 'loo' (loo is a kind of bathroom).
'a'+'loo'='ALOO'
'for' acts as a link.
(Other definitions for aloo that I've seen before include "Potato dish" , "chat in India perhaps" , "Spud" , "chat in Mumbai perhaps" , "Indian potato" .)