Grange Hill Stn - depot roads adjacent inner rail platform

Certainly, they're used all the time. They serve as the east end shunt necks for the depot, so obviously for internal shunting movements they get used. But also, any train which goes into Hainault depot from Hainault station via the wash (which is almost all of them, if everything goes to plan - actually I think all of them) will go through the wash road and then up to 70 or 71 road, before coming back into the depot. It's very common to see a train on there as you go through Grange Hill station, especially if you're travelling around 10:00/11:00.

Also trains going into the depot from Grange Hill cannot go in directly. They either have to go all the way along the wash road and up to 21/22 road (the equivalents at the west end alongside Hainault station) or reverse on the wash road, back to 70/71 road and then back into the depot. This is the more common route in my very limited experience, but the timetable decrees 21 road for train 26 (the evening peak Grange Hill via Woodford service).

Well, they seem to be there in Harsig's Central Line Eastern Extensions diagram, although I'm pretty sure today's 70 and 71 roads correspond to goods roads 75 and 76 in the diagram, with 70 and 71 roads of yesteryear no longer existing. Clearly the signalling and depot layout has also become more restrictive since Hainault depot opened.

Grange Hill closed for goods in 1965, so presumably roads 75/76 were abolished after that time. That begs two questions - what happened re a shunting neck before 1965, and are the present 70/71 on the same alignment as the old coal sidings (wide enough for the merchant's stands between them)? Presumably new track would have had to be laid before electrification anyway? These ex-GE yards were not exactly built to HST running standards; there were still 19th cent chairs in Ongar in 1968, for instance.

They can from the inner rail platform.

Four routes, 1 to the wash road and 2, 3 and 4 to various groupings of roads in the depot proper.

The former, in the same way as a train routed in from 70 or 71 road.

All routes (bar route 1 at 58) 9254-8, only allow you as far as the stop board. CM from 58 to stop board, RM from the north neck roads. Even though the route is as far as the stop boards, you know whether you're going to shed roads, outside, or outer roads depending on route number, but procedurally, the stop boards are where the north shunter should give the road number to stable on, NOT at the signals.
71 is the left road, 70 the right as you orient north in the depot, I imagine the old 'up' would've been from Woodford - Hainault

This view from a Birdseye on Bing Maps shows what appears to be 6 cars of 92TS hanging about. I saw this type of formation quite a few times when I used to drive past everyday earlier this century! 

Looks like 8 to me 😳 2 hidden by the trees

.......nope, I'm wrong, definitely 6 there

The only way I ever worked it out at the time was when a white car end was visible from the road instead of the usual red and grey and tape. I'm sure I saw battery locomotives in there once as well but I can't be certain.

Went round the loop twice today, was quite a picture between Chigwell-Grange Hill, like a wintry setting from a brothers Grimm novel