(28 Feb 2016, 7:01 am)DanPicken wrote MANviro's are allocated to the 4.

It's difficult to back this up with evidence given that Stagecoach's official fleet allocation is wrong, but MAN Enviro200s are not allocated to service 4. That, or Sunderland allocate buses incorrectly on a daily basis!

As you know, I live in Sunderland and see Stagecoach's allocations on a daily basis. The allocation is made up as follows:

Scania Gas Bus

• Service 3 - 9x Scania Gas Bus
  
• Service 13 - 11x Scania Gas Bus
  
• Service 16 - 10x Scania Gas Bus
  
• Service 20 - 5x Scania Gas Bus
  
• 5 spares
  

'09 plate ADL Enviro200

• Service 4 - 11x 09 plate ADL Enviro200
  
• Services 5/5A - 3x 09 plate ADL Enviro200
  
• 0 spares
  

'63 plate ADL Enviro200 ("Here comes the SUNderland Bus" branded)

• Services 10/11 - 10x 63 plate ADL Enviro200
  
• Service 23 - 8x 63 plate ADL Enviro200
  
• 3 spares
  

MAN Enviro200

• Service 8 - 2x MAN Enviro 200
  
• Services 18/19 - 6x MAN Enviro200
  
• 2 spares
  

MAN ALX300

• Service 12 - 4x MAN ALX300
  
• 0 spares
  

As there are no 'spare' '09 plate ADL Enviro200s, it's quite common to see other vehicle types allocated instead. There are spare gas buses, '63 plate ADL Enviro200s and MAN Enviro200s, and any of these seem to crop up. The gas buses seem to be most common, presumably because these are more fuel-efficient than a conventional diesel bus.