The phrase "hadst a go" is an informal British term that means trying something out or attempting a task. This phrase can also be replaced with other synonyms such as "had a crack at," "took a shot at," "attempted," or "endeavored to do." Other variants of this phrase include "gave it a try," "had a stab at," or "took a swing at." All of these phrases represent the concept of giving something your best effort, even if you're unsure if you will succeed. So, whether you are having a go or giving something a try, don't be afraid to take the leap and reach for success.