Would be easier to divert the 43 from Bedlington/Morpeth to just run half hourly to Blyth via Bebside, Cowpen and Isabella.
I'd also extend the 57A from Cramlington to Bedlington, or even onwards to Morpeth via Red House Farm, to provide a half hourly frequency between the Bedlington and Cramlington. Perhaps send the 57A via Shankhouse and Bedlington Bank.
RE: Arriva North East: Upcoming Service Changes