Green’s Dictionary of Slang

sawney n.2

also sawnie
[? SE sawn, i.e. the ‘sawing off’ of bacon into rashers, or the cannibalistic Sawney Beane (fl.15C), who killed people, smoked their corpses and ate them]

bacon.

[Aus]Vaux Vocab. of the Flash Lang.
[UK]H. Brandon Dict. of the Flash or Cant Lang. 167: I speeled to the crib, where I found Jim had been pulling down sawney for grub.
[UK]A. Mayhew Paved with Gold 266: The big piece of ‘sawney’ (bacon) being thrown in for nothing.
[US]Matsell Vocabulum 76: sawney Bacon; fat pork.
[UK]Leaves from Diary of Celebrated Burglar 84/2: On the table, half concealed, lay a ham and about a dozen pieces of ‘sawney’ that had just been pinched by this young band of sneak thieves.
[UK]Hotten Sl. Dict.
[Aus]Sydney Sl. Dict. 9/2: Dick went pulling down sawney for grub last week, when a cop pinched him. He’s gone in the country for a rest. Dick went stealing bacon from shop-doors for food last week, when a policeman arrested him. He’s gone to jail for one year.
[Aus]C. Crowe Aus. Sl. Dict. 69: Sawney, bacon or fat pork.
[Scot]A. McCormick Tinkler-Gypsies of Galloway 194: Bacon? ‘Sawnie,’ [said] the Cumberland tinker.

In compounds

sawney-hunter (n.)

one who steals bacon or cheese from grocers’ shops.

[UK]Devizes & Wilts. Gaz. 20 Mar. 4/3: ‘Sawney-hunters’ who purloin cheese or bacom from cheese-mongers’ shops.
[UK](con. 1840s–50s) H. Mayhew London Labour and London Poor IV 25: ‘Sawney-Hunters,’ or those who go purloining bacon from cheese-mongers’ shop-doors.
[UK]Leaves from Diary of Celebrated Burglar 84/2: Granny Dixon was in the act of ‘slinging’ some ‘posh’ to a band of young ‘sawney hunters’.
[UK]Sl. Dict.
sawney-hunting (n.)

stealing bacon from where it hung on shop doors.

[UK]H. Mayhew Comic Almanack 56: Our ‘pet pickpocket’ had been telling the little fellow of the fun it was to go ‘sawney hunting,’ which I afterwards learnt was stealing pieces of bacon from shop doors.