All the London railway stations :
Barkingside is only accessible on the eastbound platform towards Woodford. At Woodford you would need to exit the station to cross platforms. I would recommend using the highly accessible bus routes instead. TFL will not tell you about this station, but just point you at their maps which do not describe a station at all.
Underground lines : Central
Accessibility friendly : Partial. You can only enter and exit the eastbound platform for trains towards Woodford (C step 37mm/gap 213mm). Level access between street and eastbound platform only, towards Woodford.
General description :
More comment : TFL do not list Barkingside as accessible at all. Suggestion to travel towards London is to take the bus routes towards Ilford. Route 169 to Ilford, and 25 to Stratford.