snafu
Looks alright to me. As far as the rear block is concerned, I’d interpret that as sitting below the horizon. The horizon being the brow of an incline or hill. So it’s personal vanishing points would be somewhere unseen. Scaling up your graphic shows that the top left perspective line of the rear block doesn’t correspond with the left vp.
skeptik
Looks pretty much there.
The only thing slightly off is that you have base of the tall structure in the rear cut off by the horizon. You should probably show its bottom corner, just as you have with the other two.
The way you have it now makes it look like it's sticking up behind a hill. Only without the hill.