It appears the aircraft in-game in the screenshot above are holding at the CAT 3 holding points for 27L (N2E, N2W, N3) when in fact in real life they hold at the CAT 1 holding points a little closer to the runway (NB2E, NB2W, NB3).
Shuttles are domestic BA flights. They normally use alpha-numeric callsigns instead of the flight numbers used by Real Traffic. For example the LHR - MAN - LHR is always SHT 2 / 3 followed by a letter so SHT2K northbound and SHT3J southbound. The letters change throughout the day but 2 and 3 are always used for the Manchester shuttle.