Is it possible to delete an (erroneous) email address from the BT Mail app or even webmail?
Sorry meant delete an email address from my contacts.
Log onto your email account and click on the "Contacts" button in the menu bar. This will open your list of contacts.
Tick the box to the left of the contact you want to delete then either select "More" then "Delete" in the menu bar above the list of contacts or click on the "Delete" button in the menu bar above the contact's details that opened when you tick the box.