Heat a large frying pan and melt the brown sugar with sultanas until just melting.
Add malt vinegar and cook until dissolved and starting to caramelise.
Stir in apples, tomatoes, and onion, kemudian cook for 10 minutes until thickened.
Preheat the grill to high.
Grill bacon on a tray for 4-6 minutes until golden-brown and cooked.
Melt cheese and beer in a pan until smooth, then stir in mustard, Tabasco, and Worcestershire sauce.
Stir in flour and cook until the rarebit mixture has thickened.
Toast the bread slices on both sides and place them in an ovenproof dish.
Top bread with two bacon slices and spoon the rarebit mixture over the top.
Grill for 2-3 minutes until golden and bubbling, then serve with chutney.