Jon:

Perhaps you don’t understand.
Not until the discovery of the base angular casing by Howard-Vyse was there any evidence of angular casing anywhere on G1. That is what made the discovery a great find; it was the first evidence to support those who “believed” the complete structure was covered with angular casing.
Now you must stop and think for a moment...Petrie walked every course and measured the precise height at all corners. Do you not think that he would have noticed a single white limestone block with an angular side sitting all by itself and protruding “over” the inner core stones? The fact of this stone you refer to being at the upper level would have made it easier to notice than if it were at the lower level. How could
Petrie miss it?
Since the donation of Smyth’s white angular limestone casing stone that he believed came from G1 was such a great issue, then the discovery you claim by these two individuals would have made headlines...yet not a single record of the event...other than their own words.
You know and I know that several white/imported limestone blocks are used as “filler” stones at the base of G2; they are not casing stones or backing stones. I think your two observers “assumed” the stone they found to be fragments of casing when in reality it was inner core material and there are a few of them visible today.
You see...neither of them knew that 80+ inches of material is missing from “all” four sides from base to apex. If they had then they would have realized the stone was not remnant casing material.

Yours: “...The height of the casing stones on the North face is exceptional. Up to three courses of smaller stones remain on the West face. On the East face some casing stones remain but very eroded...”

Jon: Petrie measured and recorded at three levels: entrance, air shafts and course #200 and all indicated 80 + inches missing on the side of the structure. See his drawings levels 12-21 and 100-104 also his measures at course #200…section 25.
Contrary to your statement, he claims the north side, near the apex, has “less” outer casing missing...not more.
Also...please provide this group with a logical reason why the Egyptians removed the white casing along with the inner “backing” stones that really never existed. Don't forget...those three small pyramids with lots of material and without having to scramble up and down 450 feet of stone mountain.
When you do explain, can you also provide a valid engineering point of view why the builders would not interlock the casing stone to prevent it from falling apart. They did with the Bent, Red, G1 and G2...why omit G1?

Yours: “…I'm not clear what you are saying here. Are you claiming that the small pyramids only had one course of casing as well? If you are that's clearly wrong as a quick look at my photos shows up to five courses in some places still in situ…”

I’ve traveled the site also, now look at one of mine.

Explain why they didn’t cover these small pyramids completely with white import material. Again...when you return to the site, measure the height of the lowest course and compare to the one and only sample donated by Smyth. It is definitely from the west side of one of the small satellite pyramids: G1a-b or c when the road passing along their base was first constructed.

Best.
Clive