To be honest, GNE have the perfect opportunity now to nail the X21 down with a stable and robust fleet of E400MMCs (subject to any evening & Sunday interworking patterns at Consett) as the X70/X71/X72 will standalone.....and match the exact PVR of 7x to utilise 6308-14. 6334-35 should NOT fill the PVR of a route even by 1x vehicle and instead should be put into a spare role like intended.

If 9x E400MMC and 9x B5TL were swapped between Consett and Riverside (replacing CLS), you'd have:

E400MMC
- 6338-40 - X30/X31
- 6341-42 - Consett spare (low height)
- 6343-50 - X21
- 6351 - Riverside spare
- 6352-55 - X10

The above would keep the X10 & X21 the same vehicle type, handy if both put on the same rota and would give a decent spare which could last a full day on the X10.

As for Consett, there'd be enough E400MMC even if the X30/X72 interworked on Sundays (PVR 4) still leaving 1x spare.

B5TL
- 6308-14 - X70/X71/X72
- 6334-35 - Consett spare (can be used on anything except X30/X31)