You should be able to manage the Sky iD's associated with your Sky Account and remove any that you simply don't wish to use.
To do this log in to “www.sky.com/mysky” using the primary Sky iD for your Sky account then select “Additional Users” from the Profile & Settings menu.
You should see the additional Sky iD's listed and have the choice to remove them.
I hope this helps.
For more help, call to sky customer service helpline number at
http://qwikfix.co.uk/sky-contact-number.