Data Validation drop down

See attached: in particular sheet "Parameters"

Column A contains MAKE and is a named range MAKE (data in first sheet sorted by MAKE/MODEL)

Columns C onwards (row 1) contain MAKE headings (Copy/Transpose from Column A)

Under each MAKE there is list of models extracted from the first sheet using the following formula ..

in C2

=IFERROR(INDEX('MODEL SEGMENT AND DISCOUNTS'!$B$2:$B$500,SMALL(IF('MODEL SEGMENT AND DISCOUNTS'!$A$2:$A$500=Parameters!C$1,ROW($A$2:$A$500)-ROW($A$2)+1,""),ROWS($A$2:A2))),"")

Enter with Ctrl+Shift+Enter

Copy across and down

I then created named ranges (AUDI,BMW only) for each model list

Data Validation in first sheet uses List=>MAKE for MAKE and List==> =INDIRECT(D3) for MODEL

You could further sub-divide models into Diesel/Petrol (See example)