For the Cape Malay spice mix: Grind the coriander, fennel, fenugreek and mustard seeds and the cloves in a mortar and pestle or spice grinder. Mix in the cumin, turmeric, cinnamon, ground ginger, pepper and salt. Transfer to a jar.
Heat the oil in a saute pan over medium heat. Add the onions and garlic; saute for 2 minutes. Add 3 tablespoons of the spice mix, the chiles, 1 tablespoon fresh ginger, and the bay leaves and curry leaf; cook, stirring, for 1 minute.
Stir in the apricot jam and then pour in the vinegar (being careful not to breathe in the heated vinegar, as you might sneeze). Then add the soy sauce and brown sugar. Simmer over medium heat for 10 minutes. Stir in the remaining 1 teaspoon fresh ginger. Set aside half of the mixture for another use.
To finish the relish: Add the diced tomatoes, barbecue sauce and cherry tomatoes to what remains in the pan. Simmer over medium-low heat until the flavors are well infused and the cherry tomatoes are soft, 10 to 15 minutes.