Northern Fleet had a problem with the VCB causing all the units to be run on Diesel so that might have affected the numbers and reliabilityThe 769s are included in Modern Railways' monthly 'New Train TIN-watch'. The latest installment (September 2022 issue) provides the figures for 2022-23, period 3 (sorry, I'm not sure of the date range covered in each period). Here's an extract:
Fleet Fleet Size Unit Miles TINs MTIN MTIN MAANorthern class 769 8 units 22,617 6 3,770 1,123TfW class 769 9 units 28,328 13 2,179 1,587
TIN = Technical Incident (train stopped for 3 minutes or more)
MTIN = Miles per TIN
MAA = Moving Annual Average
They seem to work ok on Electric but will do less on the south side from 11 Dec.