Separate and put the sausages in a pot, generously cover them with cold water and then add the salt and vinegar – give it a bit of a stir.
Bang a lid on the pot, bring it to the boil then reduce the heat and gently simmer snags for 8 (thin) – 10 (thick) minutes before removing from the pot and draining.
Melt the butter in same pot and fry the onions and apple for approx ' 5 minutes.
Add curry powder, salt, pepper and herbs and stir over heat for 3 - 5 minutes.
Slowly add water and stock cubes and bring to the boil while stirring. Remove the skins from the sausages – good luck, try to get to them quickly, whilst performing steps 3 & 4 and before the skin starts to dry - slice thickly on an angle (4 pieces per snagger) and add to the sauce.
Reduce the heat, add sultanas and simmer for 10 - 15 minutes.
Blend the flour with 1/4 cup of water, add to the curry and stir until the sauce boils and thickens.