Using an UPDATE trigger to populate Eastings and Northings in PostgreSQL
its okay, and sorry for the bad explanation.

i got it to work as shown below:

CREATE OR REPLACE FUNCTION tf_xy_point()
  RETURNS trigger AS
$BODY$BEGIN

IF TG_OP = 'UPDATE' OR TG_OP = 'INSERT' THEN

    new.easting := ST_X(new.wkb_geometry);

    new.northing := ST_Y(new.wkb_geometry);

RETURN NEW;

END IF;
END;$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION tf_xy_point() OWNER TO postgres;
GRANT EXECUTE ON FUNCTION tf_xy_point() TO public;
GRANT EXECUTE ON FUNCTION tf_xy_point() TO postgres;


This now allows for the trigger to used as generic for any other table wishing to find the eastings and northings on UPDATE.