"You are going to look."
Translation:Vous allez regarder.
Quite right, with the qualifications you provide. Consider the meaning that is most reasonable and go with that. Remember, too, that "chercher" is a transitive verb (it requires a complement). "Regarder" may be either transitive or intransitive. So if you want to say "I'll look" meaning "I am going to look for (whatever it is we were talking about)", you could say "Je vais le/la chercher".
That’s really helpful, thanks.
I knew they wanted regarder but I felt that both might be right. But as soon as you say it I recognise that a french person would say « je vais la chercher » or in this case « tu vas la chercher », not likely to say « tu vas chercher », even though in English we would/might well.
That doesn't make any sense in French. The reason is that the French "vous allez" (or) "tu vas" may be translated as "you go" or "you are going". This is never translated into French by using être. Using a conjugation of "aller" followed by an infinitive is called futur proche (near future).