Recently I upgraded Blesta to a newer version, turns out the modifications made to the registration form were overwritten and it meant the sign-up form was asking for everything, address, telephone number and so on.
This was not an intentional change. All that is required normally is a name, country and email address, nothing else. The form has been corrected to remove all the fields not required. Thanks to those that pointed it out.
Will make a note to ensure the signup template is removed if it is included in future upgrades.