See https://www.waze.com/editor/?lon=-0.21822&lat=51.59634&zoom=6&layers=996&segments=121731819&env=row - Manor Hall Dr has U-turns allowed where it meets the A1. As far as I understand, this should not be the case in Waze. (And it would not be wise to do a U-turn there, anyway!) But I can’t correct this myself, as the A1 is locked at Level 4.
Fixed.