SELECT order_line_data
FROM           customers cus
    INNER JOIN orders ord ON ord.id_customer = cus.id
    INNER JOIN order_lines orl ON orl.id_order = ord.id
    INNER JOIN products prd1 ON prd1.id = orl.id_product
    INNER JOIN suppliers sup1 ON sup1.id = prd1.id_supplier
WHERE   cus.location = 'LONDON'
    AND ord.date_placed BETWEEN '04-JUN-10'
                        AND     '11-JUN-10'
    AND sup1.location = 'LEEDS'
    AND EXISTS ( SELECT  NULL
                 FROM  alternatives    alt
                       INNER JOIN     products prd2
                         ON prd2.id = alt.id_product_sub
                       INNER JOIN     suppliers sup2 
                         ON sup2.id = prd2.id_supplier
                 WHERE    alt.id_product = prd1.id
                       AND sup2.location != 'LEEDS' )
;