Please help me solve this sausage sizzle mystery.

It’s about the tomato sauce. Dual citizen who spent my childhood in NZ and school sausage sizzles were the best day ever. My sister and I have been trying to figure out what the tomato sauce/ketchup was. It definitely wasn’t Watties. It was almost slightly sweeter, maybe slightly spiced, not like a chutney…every time I come back I try to find it. My aunt said it was probably just the cheap ketchup they were using. It’s been driving me insane. As a side note, if anyone knows where I can reliably find a sausage sizzle in the Auckland or Taranaki area when I’m back in January, please let me know. Apparently Bunnings in Australia do them, which doesn’t really help me. What if the sauce isn’t the same?? Anyway, it’s midnight in Vancouver and I should sleep.