Welcome to Londontown!! (Oh where, oh where has ApprenticeFan gone? Melbourne?)
Looks like teams arrived around noontime at pit stop in Istanbul (sun in their faces from the South); which means that teams will be leaving in the early morning again (Hope Ron and Kelly enjoy their suite in the Four Seasons but remember to set their alarms!- or will they be having too much fun to sleep?)
Several flight possibliites from Istanbul to London: KLM LV 5:55AM, AR 10:50AM; LH LV 5:45AM AR 10:15AM; BA LV 8:55AM AR 11:05AM; or Turkish Airlives LV 8:30AM AR 10:30AM
Sunrise in mid-December is at 7:57AM and Sunset is at 3:51PM (We're far north and it is Winter: Av High 46, AV Low 34)
So if the team are arriving in mid-morning they probably are doing the ROADBLOCK at the end of the day since we see the sun setting and stadium lights being turned on. Task seems to be to perform a standard bus driver's licensing test. (Note bobby in yellow jacket behind one bus). Team members: Rob, Kelly, Meredith and Joyce, must drive big, red double-decker bus (on the way out by the way being replaced by other buses) All four seem to have real trouble backing the bus up through the pylons on the parking lot.
It looks from the amount of daylight showing that R/A and R/K are doing the task before U/J and M/G. One of these teams may have been YIELDED. Don't see anyone yielding M/G so it looks like R/A yielded U/J (just a guess at this point in time.)
DETOUR (or at least one part of the Detour) envolves a task of moving a number of blue rowboats from the Serpentine Lake in Hyde Park (central London) up a hill to a parking area. It looks like they have to move at least four boats from the lake. While we only see M/G doing this task, U/J looks like they have completed stacking their four boats (nos: 14, 24, 19, and X) and Uchenna is seen helping M/G move their fourth boat (no. 6) up the hill and then leaves them on their own to stack it onto nos. xx, 8, and 24. (And they seem to be having a lot of trouble moving that boat onto their pile.) R/K and R/A may be off doing the other Detour Task or have not arrived at the Serepentine Lake site yet.