Digressing slightly from the Gateshead and County Durham changes, I seem to recall the de-three-hundreding of the North Tyneside network around the mid 00s - with the inauguration of the 1 / 2 etc - was so single and double digit route numbers would be allegedly be easier to read from afar.

I may be mistaken here but such was the Go North East logic at the time I recollect they also introduced the 40C / 41C / 83A / 83C(!)