The location of a supplier is defined[1] to include the following: –
(a) where a supply is made from a place of business for which the registration has been obtained, the location of such place of business;
(b) where a supply is made from a place other than the place of business for which registration has been obtained (a fixed establishment elsewhere), the location of such fixed establishment;
(c) where a supply is made from more than one establishment, whether the place of business or fixed establishment, the location of the establishment most directly concerned with the supply; and
(d) in absence of such places, the location of the usual place of residence of the supplier.
Source Taxguru