Some more research into the mythical Boxing Day staircase race turns out that it was never a race, just a fun ride, through the stepped streets of Kingsdown. That's a tradition to bring back, down Spring Hill. Normally that only gets coverage here at the top, where it becomes gentle enough to allow motor vehicles to park across the road. Further down, it's stepped.
The middle section has some barriers at the top to stop you entering at speed, but then there's a fairly straight run with a dropoff to Dove Street, one with inadequate visibility to be sure there isn't something about to run you over.
You have to cross that road to enter the final descent
This is a number of flights of stairs, none on their own too hard, with some runouts to allow you to change your mid or just drop a bit of speed. It then levels off into a good runout stretch into the dispersion zone that is King Square.
This would be a great place for a Downhill Race, "Kingsdown Technical". The square would be where the finish would be, the audience would get a fantastic view of the bikes coming down at speed.
This is something to think about. It would be an exciting Cycling City event - a downhill run in the heart of town, where anyone can come to see it. It would make for some great photos of the city and make up for some of the bad press it's been getting in the cycling world, with its recent war-on-pavement-cycling. Hold the event on a Sunday and there's no through traffic to speak of; closing the roads wouldn't be hard. And if it can't be done officially, it would be a good night-time event.