I bought a small beef roast for the family cause I never cook roast and thought they'd enjoy it but... I don't know how long to cook it for.

It's only .672kg so it's only tiny. I was thinking it would only need about 45mins on about 190*C - not fan forced. Am I thinking along the right track?

I was also going to rub it with seeded mustard and crushed garlic. What do you think?