The mods are being done in phases. Ilford only has so much room, so once the interior strip and relivery has been done they’re coming back to GWR to make room for other units to be done. ETCS has been fitted to one unit so far; this needs validation before they do the others. Validation requires engineering access to Heathrow branch, which is hard to come by ordinarily- never mind with both GWR and XR wanting such access in the near term.
It was early 2019 the 319s arrived at Reading for driver training. Issues raised by the union need to be addressed before they can go out on the Mainline. The number of 319s coming to Reading to aid the driver training programme was not specified; only that a number would be based at Reading for driver training before going for conversion later once the first 769s have been delivered. That hasn’t changed in itself, just the 769 delivery date has slipped.
Aren’t they? That’s completely at odds with everything we’ve been briefed on them so far, wouldn’t explain why the interiors have been completely gutted, and isn’t what bombardier have been contracted to do.
EDIT sorry it was December the first unit arrived, thread here:
https://www.railforums.co.uk/threads/gwr-class-319-769-information-discussion.174866/