(24 Feb 2014, 5:36 pm)tyresmoke wrote 24s are allocated DAF deckers too... One works the 24X too.
You're right, but Lowlanders and ALX400s are common on the boards which do not require double decker operation despite this. Indeed the Geminis made a few appearances prior to gaining branding for services X1/X2 likewise...
Very much one of those services where 'anything goes'. Same goes for the other two as well.