(24 Feb 2016, 7:59 am)Jimmi wrote Is it not peak time service X6 Cobalt - Newcastle that some of the 306's drop onto? I know at least one used to when it was still numbered as the X9. https://flic.kr/p/rMphaL
Think one run interworks with a scholars service as well, which I think is the double decker run.
306s do indeed drop out to do X6s. Unless it changed in September, the school turn also did the 554s.