Here we see three vehicles, all of which made rational decisions, and by doing so created a traffic jam in Kingsdown. Their mistake: trying to get a vehicle onto Somerset Street.
The far vehicle is loading scaffolding; Somerset Street is to narrow for it to park, even if there was room. The other two vehicles wanted to get through. The UPS delivery van has recognised this isn't going to work, and instead stuck his hazards on and walked out to do the delivery. The Golf in the middle is now boxed in. They're going to try the "pavement gambit", but there's a big drop here and the pavement lined with metal: theres a serious risk of tyre damage. Which means they are stuck until the UPS van driver comes and both vehicles can reverse out.
The kingsdown residents association are strongly pro-CPZ, so that they and their visitors can park near their houses. Here's an alternative idea: make somerset street pedestrians, cycles and horses only. With the cobbles, its a lovely street, and if it was blocked off to non-motorised traffic, it would make it unique in the city.