Ditchling has always seemed a bit daunting when I've hit it, but that's because it's always been at the end of a FNRttC, so you're tired (sleepy) and a little knackered. I've also mostly tried to go up it with a single-speed, which admittedly has easier gearing than most of the people who I've seen ride it on fixed, but it still doesn't make it fun.
The one time I've actually cycled all the way up (the last Brighton FNRttC, I think this was the easy ride, the day before the Dun Run), I was using gears on the Kaffenback, and didn't actually find it too bad at all. I'm not saying I would want to cycle down and do it again, but compared to the hills out of Cheltenham that I used to cycle when I lived there, it's quite short, and not excessively steep.
It's marked as a single chevron on the OS maps, but I think it's possibly only just in the range to qualify for that.
Of course, after living in London for a few years, it's a lot steeper than pretty much everything around here. These days I consider some of the Thames bridges to be hills.