That's why I think a 3-car (c156,c150,c158 or c155 with mods + c153 without mods) would satisfy the regulations. So long as one part of the train is accessible then the c153 need not be modified.
Besides, chances are the wheelchair occupant won't even be able to make it onto the platform at most stations, most high-streets having curb stones preventing any reliable access, let alone the only access being a footbridge to cross to the adjacent platform entrance.
This option would also allow the use of 2-car units in off-peak, with c153 connected for peak traffic flows requiring 3-car unit. The only restriction to this flexibility would be the inability to use the c153 in isolation.
Besides, chances are the wheelchair occupant won't even be able to make it onto the platform at most stations, most high-streets having curb stones preventing any reliable access, let alone the only access being a footbridge to cross to the adjacent platform entrance.
This option would also allow the use of 2-car units in off-peak, with c153 connected for peak traffic flows requiring 3-car unit. The only restriction to this flexibility would be the inability to use the c153 in isolation.