Bounds Green LU and Bowes Park NR. Neither are wheelchair accessible at the moment, and while Bounds Green is well sited, Bowes Park is hidden in back streets.
Bounds Green LU platforms are about 16 metres below ground, which means a new wheelchair-friendly 1:20 slope up from the centre of the tube platforms towards the southeast would come to the surface 320 metres away, roughly where the NR line crosses Bounds Green Road. The slope would be under Bounds Green Road, making construction easier. A 120m level walkway could be constructed from the same place alongside the railway to the southern end of the NR platforms, and then a short bridge over one track to the island platform, and then a 100 metre ramp down to reach the platform alongside the existing staircase (which would be retained). The Bowes Park platform building would have to be demolished for the ramp, but I doubt if many will miss it. I can't see travelators being viable in either ramp. All existing entrances to either station would be retained.