OSRM and Graphopper recommend cars use this service road (for access to the playing field only) to short cut from Boston Manor Road to Swyncombe Avenue avoiding the turn restrictions at the mini roundabout. There's a gate at the northern end of this road which I've changed to "access=private", but:
1) I'm not sure if this is enough (I know the two routing engines only update their view of the network periodically, but either my change isn't enough, or they haven't updated yet)
2) I'm not sure if there's a gate at the southern end. Regardless of the routing implications, it would be good to fix this if there's one there.