Someone with better search skills than me may be able to find the doc that was published on here a few years ago when TFL or the council checked the speeds on the local roads and found that the average speed going up Manor Mount was 23 mph but the shocker was that the average speed going down was 43 mph and it a no entry.
There is the occasional camera car parked there and I have seen a police check once to catch speeders on Waldenshaw and wrong way drivers on Manor Mount. The roads were very quite for a few weeks after that.
The problem is that quite a few people who live on Manor Mount drive the wrong way down the hill to "save time". You know who you are.