(10 Nov 2015, 7:54 pm)GX03 SVC wrote If thats the case, tell me why it doesnt carry X21/X22 branding.

It doesn't carry branding because it's an all routes spare. However, it's PRIMARY purpose is to provide backup for the X21/X22 and therefore, it is not a rare and odd working when it appears on these routes as needed. However, due to it being an all routes spare, it can be used on other Ashington routes and be classed as a rare and odd working. Look at GNE's examples below:

6116 or 6117: X39/309/310 = Correct allocation, 1/9/17/40/41/80/327 = Rare and Odd Working.

6099/6100: 56 = Correct allocation, 9/20/X36 = Rare and Odd Working.

6084= 10a/10b/X9/X10 (inc any scheduled odd workings, any evening boards which include the full 10 but finish at Riverside) = Correct allocation, any other Riverside route including any evening boards which include the 10 and finish at Hexham = Rare and odd working