It would be fascinating to know the true cost of the fleet's refurbishment vs. the life (and returns) provided. One of the costliest aborted programmes of late I imagine.
It begs the question of the real railway operating insight possessed by those who decided that their refurbishment and subsequent integration into timetables operated by newer stock was feasible.What is little known about these units is the complications they cause in timetabling them amongst the 377s. With longer dwell times, poor acceleration and only 9%g braking, various fudges and fiddles have been put into the Brighton Main Line timetable to get it to work.
Unfortunately, as is plain to see, the various fudges and fiddles don't work, and these units have been demonstrated through detailed analysis to be a notable contributor to the underlying poor performance of the Brighton line. (Without going into detail, the base timetable is responsible for twice as many % PPM failures on Southern than any other south east operator).
The same would apply if they were put on to any other intensively worked railway that had a fleet formed of rolling stock that performs consistently, eg SE or SWT.
The traction equipment is also remarkably 'noisy', to the extent that it is suspected to regularly cause signal failures. Several this year alone, including a couple at London Bridge.
Their best hope for the future is as hauled stock.