Defra rules quite expicity state: "It is permissible to source certain types of former foodstuffs, as well as fruit and vegetables, from non-catering premises for feeding to pigs but this can only be done from those premises that either do not handle materials banned from being fed to pigs , or have HACCP procedures in place to ensure complete seperation from prohibited materials, and these procedures have been agreed with the local authority"
There are plenty of meat products found in most bakeries such as sausage rolls, pizzas, sandwich fillings, even lardy cake. Also items where eggs are the main ingredient such as quiches are banned.
As for milk, unless it is waste from your own cows, can only be fed to pigs if a licence is granted by Defra.