Car power supply to LCD

Hi ive purchased a 8" tv / lcd screen for the car that says for auto /office etc but the power only came with a 240v mains power pack.

Is there a small circuit i can make to put between the ciggy lighter socket and lcd to ensure the correct power?
Details are.

Powersupply 240v > 12v - 1.5a

The instruction book says

11.5v to 13v - 1.2A


Cheers

This regulator https://www.st.com/stonline/books/pdf/docs/2141.pdf looks pretty close to what you need. It's L4940XX12 from ST electronics.