Presumably these will be guarded whilst in service so how will this work as they were DOO at GN?
They have like the vast majority of trains in service got the controls to be driver or guard operated.
165 and 166 until modded by GWR were about the only pre 2000s train to be solely driver door operation with the guard having to use the signal buzzer. The class 220 and 221 are the others.
Nearly if not everything else (395 excepted?) has the facility to be guard door operation as it generally either has or does operate with a guard or is derived from a guard operated train - even the 700s have guard's door panels.
365s were guard operated with South Eastern.
317s were guard operated on the WCML.
357s were guard operated on the LTS for 12 cars (until recently) - you get the picture.
It's much more economical to provide both as it gives the sets a larger potential operating area.