The NCN route is my preferred Market Hill Avoidance. One short, narrow section is technically footpath, then there's the steep exit from the Salt Works that needs a brisk fixie stomp.
Basically: turn L IMM after the bridge over the tidal Blackwater, follow the NCN signs, SO @ Salt Works and then R @ T to bring you up to the High Street; L to continue on the official route out to Mundon and Latchingdon.