Is the 787 to big ? just found this on NATS airport info.
B787 available taxi routes:
Departure Runway 09:
Taxiway Z to Taxiway G, enter Runway at GX.
Runway 27: Taxiway Z to Taxiway A, enter Runway at AX.
Arrival
Runway 09: Runway to vacate either BX (Taxiway B) or AX (Taxiway A) to Taxiway Z to allocated stand.
Runway 27: Runway to vacate GX, Taxiways G and Z to allocated stand.
(h) B787 aircraft will not be able to backtrack.