"Taking a look" or "having a glance" could be used as synonyms for the phrase "hadst gander". It refers to quickly inspecting or observing something in a casual manner. Other similar phrases might include "checking out", "scoping out", or "surveying" something. These phrases can be used in a variety of contexts, from assessing a situation to simply satisfying one's curiosity. Overall, having a "gander" at something is an informal way of describing a quick inspection or observation, and there are many different phrases that can be used to convey the same idea.