Lillian,
Not sure why you think a pet pig is different to a farm pig as to disposal?
Is this different in Scotland to England?, I would doubt this as EC 1774/2002 is pretty clear, and does not allow a derogation by member states.
In England Burial of animals comes under the Animal By-Products Regulations 2005 which implement EC1774/2002.
Part 6 sections 28 of these regulations states :
"28. In accordance with Article 24(1)(a) of the Community Regulation, dead pet animals may be buried."
The "community regulation" referred to is EC1774/2002.
Article 2 of EC1774/2002 defines a pet animal as "“any animal belonging to species normally nourished and kept, but not consumed, by humans for purposes other than farming;”
The key word here is "normally” and since pigs are normally kept for meat, they cannot be buried, and must be disposed of in accordance with the Animal By-Products regulations, which is via a state approved disposer.
Page 11 of the attached Defra leaflet (which seems to cover Scotland as well) makes this clear.
http://animalhealth.defra.gov.uk/about/publications/advice-guidance/documents/pet_pigs.pdf