(17 Dec 2019, 4:38 pm)DH9 wrote 6 to return to half hourly along its entire route?

Its had major timing problems since last change on 29th July 2019.

There's been issues with timing on a lot of services with the changes that have happened over the past year or so. It seems they've been trying to streamline the services to save money, but at the expense of reliability.
As I mentioned above, since the X21 and 18 were combined, the reliability of what was the 18 route has gone to pot. After say 3pm you may as well ignore the timetable, it very rarely runs on time because of the traffic along the route, there have have been several occasions where they've just turned it around in Bishop because of how late they are, which never happened with the 18 unless there was an incident with the bus.
Obviously I don't have exact figures, but I'd guess a good 75%+ of passengers who travel on that part of the route are just going between Woodhouse Estate and Bishop rather than travelling on to Newcastle, so they have little incentive to travel with GNE, in fact I'd be willing to bet that since they extended the X21, passenger numbers on that part of the route have decreased with people just using the Arriva 6 instead (that's what I'd do if I wasn't already paying for a GNE pass).

Having said that, it's really nice to have direct connection to Newcastle as it was always a pain changing, the X21 would pull away as the 18 was pulling into the bus station, and vice versa!