When I compared the vehicle-json with Import CSV/TSV fields, I found that's many fields that have not been included on the JSON. Here's a summary, the field with a question mark does not exist on JSON
StockNo - Identification- StockNumber
DealerCode - Seller- Identification - LegacyId
ManuYear → BuildDate → Year
Make - Specification.Make
Model - Specification.Model
Series - Specification.Series
Badge - Specification.Attributes.Badge
Body - Specification.Attributes.Body
Doors - Specification.Attributes.Doors
Seats - Specification.Attributes.Seats
BodyColour - see Colours Exterior
TrimColour - see Colours Interior
Gears - Specification.Attributes.Gears
Gearbox - Specification.Attributes.Transmission
FuelType - Specification.Attributes.FuelType
Retail - SaleType? see ListingType, SaleStatus & SaleType
Rego - see Registration
Odometer - OdometerReadings
Cylinders - see Specification Attributes Cylinders
EngineCapacity - see Specification Attributes EngineSize
VINNumber - see Identification VIN
EngineNumber - n/a. Not a value we have to provide
ManuMonth - BuildDate → Month
Options - Detailed vehicle options are only provided to RedBook subscribers
Comments - see Description
NVIC - We only use RedBook data, see Specification SpecificationCode
IsDemo - see ListingType, if the vehicle is an applicable selected demonstrator, it will be sent with "Demo".
DriveAwayPrice - see PriceList DAP
PorscheCertification - if applicable see Certifications
NUD - n/a
OriginalPrice - n/a. we only supply the vehicles listed price, ee PriceList EGC&DAP
IsApproved → With regards to the approved certification, if the vehicle is flagged, it will be included within the "Certifications" fields, the example provided notes "Porsche Approved Vehicle".