(23 Aug 2015, 5:53 pm)Jimmi wrote Well Arriva did renumber the X14 as the X66 as it runs along the A66.
There are many more up and down the country.
The X62 between Hull and Leeds jumps out. Although it is Stagecoach.
There was also the short lived X19 to Doxford Park. Which was Arriva.