I think this little snippet constitutes a rare/odd working.

Looking at Bus Times today, it seems that Go North East are operating a new service (999) around the Wakefield area using 6346 (YX70 OHW).

This makes sense actually. As Lothian have recently migrated south of the border, operating around Consett and Stanley, it would be expedient of Go North East to look at Yorkshire to potentially expand their operations.