Flag of Malta — unofficial construction sheet
This construction sheet uses a mix of both official and unofficial dimensions. See below for details.
Own work.From Malta's constitution...

(1) The National Flag of Malta consists of two equal vertical stripes, white in the hoist and red in the fly.
(2) A representation of the George Cross awarded to Malta by His Majesty King George the Sixth on the 15th April, 1942 is carried, edged with red, in the canton of the white stripe.— Constitution of Malta — Article 3.

The George Cross medal referenced in the constitution currently resides in Malta's National War Museum. See w:Award of the George Cross to Malta.

The specifications for the flag are documented in an official government document titled Graphical Specifications for the National Flag of Malta. Publication date is 2008.
The government specification document suffers from an extreme lack of quality:

The specification drawing on page 2 uses a low resolution image instead of a detailed drawing to depict the cross. The image is likely produced from a pencil rubbing. Quite simply, it does not provide sufficient detail to properly reproduce the flag.
The placement of dimension arrows is not precise which leaves room for misinterpretation.
The red fimbriation is drawn so poorly that it partially obscures the four "G-VI" symbols.
At the bottom of the cross there is an unexplained gap between the fimbriation and the medal.
The ratio of the cross arm width to cross arm length (D:C) does not match measurements taken from photographs of the real 1942 George Cross medal.
The ratios of the cross arm width to each of the two circle diameters (D:H &amp; D:I) do  not match measurements taken from photographs of the real 1942 George Cross medal. The diameters of the two circles are much smaller than they should be; this distorts the look of the cross and it interferes with the proper placement of the four "G-VI" symbols.
Based on values of C, F, &amp; G, the value of E cannot be 16 as specified. E needs to be 19 or alternatively one of the other dimensions has to be modified.
The only colours mentioned in the specification document are white, black, and red.  There is no mention of the colour grey which is traditionally used to represent the color silver on Malta's flag.
The corners of the red fimbriation on the specification drawing appear to be rounded. The rounding is sloppy and not very consistent. Most photos of the flag show square corners. The Olympic flag manuals also show square corners.  There is a note below the specification drawing that states "Note: this diagram is provided for reference only. It is not intended for reproduction". Perhaps the rounded corners should be ignored because there is no verbiage that actually says they should be rounded.Proof that the background of the George Cross should be coloured grey instead of white is provided in a 2022 government contract with Zaffarese Signs + Display Ltd. The contract reads

The National Flags must bear the George Cross emblem in silver grey background with black letters, circles and St. George.— 2022 government contract for the procurement of national flags

Unfortunately the contract does not provide RGB or Pantone colour codes to use for silver gray.
More notes on the 2020 procurement contract:

the contract contains its own flag images which are worse than the ones in the official specification document.  The contract repeats all the same dimensions that are defined in the specification document without actually referencing the specification document.
the flag images in the contract show square corners on the red fimbriation.
The specified diameters of the two circles are marked as being approximate.
The  dimensions of C, D, E, &amp; G are allowed to vary by up to 15% !Reading between the lines, this looks like an unofficial acknowledgement that the official specifications are flawed and the flag manufacturer is free to adjust the dimensions as it sees fit.

Britannica, claims there should be two shades of grey; the implication is that the black colour used to be a dark shade of gray.  Indeed, the 2012 London Olympic manual shows two shades of grey (Pantone 430C &amp; 432C) with no black.

By looking at photographs of assorted George Cross medals , it is clear that the medals comes in two varieties. Let's call them "type 1" and "type 2" for lack of better terminology.

Type 1 medals have a perfect circular backing layer that holds all four G-VI symbols. This backing layer is concentric with the cross itself. The backing layer extends slightly beyond each letter G and it leaves room for serifs on the letters V &amp; I.
Type 2 medals have a non-circular backing layer that does not protrude past the edge of the letter G.The difference is normally subtle, but when when a thick red fimbriation has to be drawn around the medal, the difference becomes very noticeable.
Malta's 1942 George Cross medal is a type 2 medal.  Therefore the red fimbriation needs to follow the outer edge each letter G without leaving a gap.  This path, as it brushes past each letter G, can be approximated with an elliptical arc or a Bézier curve curve.
On some flag images, (including the drawing in the contract referenced above), the fimbriation is drawn with circular arcs that match a type 1 cross. This should probably be considered to be an error.
Note also that the flag shown at Vexilla Mundi manages to make the red fimbriation follow a true circular path along the outside of the letter G. This is only possible because the letter G on the Vexilla Mundi drawings has been heavily distorted.

On all real George Cross medals, the object that sits at the bottom of the disc containing the FOR GALLANTRY inscription is presumed to be a five petal Tudor rose. On some drawings, flags, and carvings, the rose is replaced with one of:

a styled cross e.g. File:GCstone.jpg
a plus sign (this is how it is depicted in the flags used at the Olympics)
a plus sign embedded in a diamond
a bunch of dots
a pentagram (five pointed star) as shown in Album des pavillons
a four spoked asterisk
an unrecognizable blobAbout this construction sheet:

This construction sheet honours dimensions A, B, D, F, &amp; G from the official specification document.
The official values for E, C, H, &amp; I are considered to be at odds with the constitution as they do not form a true representation of Malta's 1942 George Cross.  All five values have been replaced on this construction sheet with values measured from File:George Cross Malta P1440218.jpg; this is why the description of this file reads unofficial construction sheet.
The background of the George Cross on this construction sheet is coloured with a single shade of gray. The lettering is solid black and all of the other features are delineated with black lines or curves.
The image of St. George and the Dragon is traced from photographs of several different medals.
Some minor anatomical features have intentionally been omitted because with only two colours (grey and black), the drawing suffers from a very cluttered look.
The red fimbriation is shown with square corners.Reference images of assorted George Crosses:

File:George Cross Malta P1440218.jpg This is Malta's George Cross. (Type 2)
nickmetcalfe.co.uk (Type 2... same as Malta's George Cross)
museum.wales (Type 1).
MapGrid