Need some help translating this pot roast recipe to UK ingredients

Heard good things about a Mississippi pot roast but honestly don't know what the British equivalent of the items ard. Sounds ridiculous I know...

Any help is appreciated

1 (3-4 pounds) chuck roast

1 packet ranch dressing mix

1 packet au jus gravy mix

¼ cup butter

4-5 pepperoncini peppers

bon appetit