I made the mistake of skipping the FQDN when setting this up thinking I could just set it afterwards, was too lazy to update my dnsmasq entries. On the bright side, updating it isn’t so bad.
Login to vCenter, hop to access and click ‘Edit’ up in the top right hand side.
Login via SSH, type
shell to open a new bash screen.
Hit 3 for hostname, type in the new value you want and hit enter, then 1 to exit.
This does not require a reboot or anything either, nice!
Ensure your internal DNS reflects the new settings and you're good to go.