Boards
just wrote this formula
=IFERROR(IF(VLOOKUP(E2,'List'!A:B,2,FALSE)="Red","140633-5000-000",IF(VLOOKUP(E2,'List'!A:B,2,FALSE)="Blue","140639-5000-000",(IF(E2="Green",("290010"&"-"&"5000"&(IFERROR(VLOOKUP(E2,'Form'!B:C,2,FALSE),"-000"))),(G2&"-"&E2&(IFERROR(VLOOKUP(E2,'Form'!B:C,2,FALSE),"-000"))))))),0)
worked first time.