Importing email to iCloud mail account

I am in the UK and have a Virgin Media email account (ntlworld.com) that I want to import the contents of to my iCloud.com mail account but the instructions on my iPhone XR and my iPad mini 5(both running iOS 18.7.1) don’t match those on the online Apple ICloud help pages for importing email.

When I click on ‘import email’ in the iCloud mail settings I only get a choice of Yahoo and Outlook on the pick a provider screen and I can’t work out how to proceed any further to get my NTL email imported.

Can anyone on here help me to complete this task so my NTL emails will be safe in my ICloud mail account for when I leave Virgin Media and that account eventually gets closed.

Many Thanks