It didn’t Tony – DD & Fig8 were always different things, the DD usually being at the end of a meeting, for whichever Bangers were worth putting in for a final blast before scrapping.
Incarace used to host the World Destruction Derby once a year, but ditched it after metal prices went up and cars became harder to find at low cost. Most Fig8 races featured Street Stox which were like Bangers but more heavily armoured.
If you were a kid watching DDs, chances are you remembered the Fig8 because in the DD you can use any part of the track so you’ll have seen cars using the intersection. It’s possible you’ll have seen Banger Fig8 races though – they used to be popular. They’re less so now. Like I said, metal prices have gone up so drivers try to keep cars going for as long as possible. Safety has become an issue too – some years ago at Buxton there was an horrific freak accident that nearly killed a driver (I got a great pic but would never publish it) and it’s made promoters think twice about running these races.