Asda online only permits "allow substitutes" with a yes or no option covering all items. Tesco permits "allow substitute" with a yes or no option on each individual item - and allow precise instructions such as "only Rosso - not Dry or extra dry Vermouth". This means that incompetent or under skilled pickers cannot send totally inappropriate substitute items - as happens frequently with ASDA online. Asda has not kept up with internet technological advances and the website is not interactive to the same degree as its main competitors, which is why I have stopped using the inadequate service. Shop floor, stockroom, warehouse and delivery staff are let down by useless administration and Asda will continue to haemorrhage customers to more competent competition - so goodbye Asda and hello Tesco and Sainsbury. Edward James.