We’re are going to London in a 1.0 Fiesta which we know nothing about?Watch
You’ll be fine. Just don’t overwork the engine. By that I mean don’t be a boy racer and go easy on the accelerator, stick to the slow lane, and don’t weave in and out of traffic too much.
Main thing if you're taking several people on a long trip IMO is not to get distracted by talking to them or showing off and having a crash.
remember to take breaks so you don't get driver fatigue.