S1 seems to be the direct service via Clifton, so I'd assume the S2 would run between Stannington to Morpeth via Stannington Station, Hepscott and Stobhill.
S1 seems to be the direct service via Clifton, so I'd assume the S2 would run between Stannington to Morpeth via Stannington Station, Hepscott and Stobhill.