Unfortunately, the helmet is one of our very few sources to actually show us early Anglo-Saxon grooming preferences. Mid-late Anglo-Saxon pennies, especially from the ninth century onwards, often feature royal portraits on their obverse designs, but these are very small and inherently stylised. Some, like London pennies of Alfred, do have a suggestion of a beard.

One of the interesting sources we do have is Orderic Vitalis' history of the Battle of Hastings in 1066. According to him, on the eve of the battle, Harold inspired the Anglo-Saxon troops by mocking the Normans for having short hair and for being clean shaven, claiming they weren't manly enough to grow beards. On the other hand, apparently the Norman captains inspired their men by mocking the Anglo-Saxons for having long hair and wearing tunics, calling them women in dresses.

We also have some illustrations from illuminated manuscripts, although again these tend to be stylised. They do tend to show men with full beards.

It's worth mentioning that the mustache also forms the tail of a bird. It's possible that the mustache wasn't particularly common, but was selected with artistic licence to complete the design.