Neil
That's an excellent find. I have a number of friends who are members at Shipley and I play there on a regular basis. I would never have recognised that as Shipley had you put the picture up with the caption "which course is this?"
The only photograph I could find on the web of the current 7th green is this one, taken from the club's website
This is taken from in front of the green whereas Frith's is from the hillside behind the green. The current green is considerably smaller, with what we in Yorkshire refer to as a "reverse MacKenzie step" with the top tier of the green being higher than the lower tier. There is also a fronting bunker, intended to catch any attempt to land short of the green and bump the ball onto the green, which does not appear to be part of MacKenzie's orginal design. There are also considerably more trees on the course, you cannot now see the 6th green (shown in the top of Frith's photograph) from the 7th green.
I would guess that where the couple are standing in Frith's photograph is near where the current photograph is taken from.
It is an intimidating par 3 but I have always thought that it is unfair to class the beck which runs down the side of the hole and then behind the green as out of bounds rather than as a water hazard.
The first of the other two Shipley photographs is taken from the hillside above the course, looking over the course to the clubsite. The second photograph is (I think) of the 14th green although again the addition of trees makes it difficult to recognise.
I was in Grange over Sands recently and drove past the golf course. I did not know it was attributed to MacKenzie. As you state it is laid out on very flat land, close to the Morecambe Bay estuary.