I'm just guessing that service X6 and X7 would be hourly and X5 maybe half hourly between Peterlee and Sunderland and hourly between Peterlee and Hartlepool, providing a 30 minute frequency between Hartlepool and Peterlee with service X6, with service X6 and X7 providing a bus half hourly between Sunderland and Peterlee.
unless Dan wants to share information with other members of this fourm.
RE: Go North East: Upcoming Service Changes v2