(Yesterday, 7:53 pm)Storx wrote I'd imagine it'll be the 6 Daimler ones being used on it currently, plus the 2 new ones (there's 6 at Riverside I'm sure). 

I don't know for certain but I still think that the ones on the X45 were meant to be on the X21 and the 6 likely remaining on the X21 were meant to be on the X45.

No doubt been swapped around to shut up local stakeholders.

Ones at Consett seem to be split between 47/X45 with no confirmation which service they're actually meant to be allocated to. 

There is only 4 at Riverside which are 6397-6400 that are being allocated here, there and everywhere at the moment.

It would make sense at this point to put them on the X10 with 6377 as a spare, then have 6348-6355 on the X21.