Do you have a link for these pages so we can take a look?
From The National Archives website (National= UK). The UFO stuff was free to download but you have to open an account.
File DEFE 31/180/1. "UFO incidents; with redactions", dated 20 June 1991 - 10 March 1992.
Pages 36, 37. A lot of empty space, but I decided to post the pages whole. Not sure what the yellow dialogue box means (it is part of the image as downloaded):
Pages 54, 55, 56. Page 55 is interesting.
Page 55 includes the intriguing line
"...but sensitivity of material suggests very special handling"
marking it out as the form that David Clarke refers to on his blog "Dr David Clarke Folklore and Journalism"
17th para / text block down.
As far as I can see, the only link with the Calvine image in pages 54-56 is the reference to the requested task being
"A RETASK OF AN ORIGINAL PASSED IN SEP. 90" [Capitals in original] and the reference to
"..5 (FIVE) VU-FOILS..." (Sic?) but I think the connection is there.
Note for younger metabunkers- a viewfoil was a transparent, flexible sheet, often A4 paper size, which could be printed on or written/ drawn on with marker-style pens. An overhead projector was used to project the image onto a whiteboard. I don't think I've heard the term for 25 years! Before "Powerpoint" and the like, an OHP and viewfoils (AKA transparencies, acetates) were widely used for presentations and as teaching aids in offices, classrooms etc.
I must admit, while my suspicion is that the Calvine photo is a hoax, probably along the lines demonstrated by Wim Van Utrecht
(A Christmas tree decoration or similar, and possibly a model Harrier, hung on fishing line), "Page 55" (above) has me wondering if the diamond is indeed a flying craft as claimed (although I also think that that would be extraordinary).
Immediately before the "Calvine pictures" in DEFE 31/180/1 (i.e., originally filed immediately after
the Calvine pics) there are a number of pages from Aviation Week and Space Technology
magazine, cell-phone shots of the originals have already been posted by Duke.
I don't know if their inclusion in DEFE 31/180/1 next to the Calvine pics is significant, or coincidence. As stated in an earlier post the materials appear to be in chronological order, the Calvine pictures and the AW&ST pages were both filed between the 3rd and 5th of February 1992 inclusive.
These are the relevant pages (28-35), I don't want those who aren't interested to get scrolling fatigue so click to enlarge!
The image from DEFE 31/180/1 page 30, copied from Aviation Week & Space Technology
December 1990 does have a resemblance, as Duke and former member Rory have pointed out.
I would be surprised if whoever was responsible for the "UFO file" hadn't noticed the similarity between this and the Calvine picture considering they were filed within two days of each other, so maybe these images following the Calvine picture wasn't a coincidence.
(Here's a clearer image, borrowed from David Clarke's blog, link as above):
(I find the detail of the weapon-release mechanism utterly unconvincing, though- seems a bit pointless having such an amazing aircraft if you then have to slow down directly over the target and use big springs to deliver stores apparently modelled on WW1 artillery shells).
The pdf of National Archives file DEFE 31/180/1, "UFO incidents; with redactions" is attached,
pdf, 36.6MB, 204 pages.
EDITED 07/04/23- I meant to say "Page 55 is interesting." Page 56 is boring as.