Is there any indication that Aecom actually drove through the junction at all? I fail to see how anyone turning left at this junction could believe it is a well-planned turn.
Also, there is no real reason why this shouldn't be two lanes at the end, enabling cars turning right not to block the predominant flow of traffic turning left. Finally there is probably one too many crossings - the one between the junction and the zebra crossing is probably unnecessary.
Google streetview still shows this junction prior to Southwark's balls-up...
And if you go further back on Streetview, you can still see when the primary route went along Calton Avenue.