With all respect to a number of other expert & credible (most important) references, including Porters 3rd Edition Original Jaguar XK; the BEST source of reliable/accurate and 100% credible information on XK Paint and Trim colours is Anders CLausagers’ JAGUAR XK140/150 In Detail, researched and written when he was chief archivist for the JDHT, where he did a 100% search of all the factory, now JDHT records, and put it on a data base, thus allowing generation of all the statistics on paint colours and trim colours and their combinations…
RE the XK140 OTS, of those made, some 3185 were supplied in “Standard” paint colours and trim colours and paint/trim combinations, leaving 171 others for a total of 3356 XK140 OTS made.
Of these 3185 only 19 were supplied with DOVE GREY paint, and all 19 had SUEDE GREEN trim, 2 with a FAWN hood colour and 17 with a FRENCH GREY hood colour.
In addition of the 171 XK140s not with a ‘Standard’ colour/trim combination, another 24 were supplied with DOVE GREY paint (standard), of which 4 had BISCUIT trim, 9 had RED trim and 11 had TAN trim, so three ‘standard’ trim colours, but their combinations with DOVE GREY was non-standard.
Now in these published Colour/Trim statistics Anders notes that ‘many cars had trim with a contrast piping colour’ but he does not differentiate them from matching colour piping in his overall statistics, but clearly this information is held by the JDHT thus Tom’s Heritage Certificate advising DOVE GREY with SUEDE GREEN piped biscuit, and I note that I have always accepted that that wording means SUEDE GREEN being the main trim colour, with the piping (where used - seats, dash) was BISCUIT, and not the other way around.
So Tom’s car is one of the 19 cars considered to have a ‘standard’ DOVE GREY with SUEDE GREEN Trim colour combination, (don’t know whether one of the 2 with Fawn or 17 with French Grey hood) and not one of the 24 ‘non-standard’ cars, albeit four of these did have BISCUIT as their trim colour.
How many of the 19 cars DOVE GREY with SUEDE GREEN interior had Biscuit piping is anyone’s guess - at least one (given Tom’s Heritage Certificate) but no idea about the other 18 unless they survive or have a Heritage Certificate, as the JDHT will know of course, but wont give out such information…