I will try to help you.
While sending mail, you have to give the full mail id.
Also you have to sent mail to yourself and check whether its getting into your inBox.
While typing your mail id give the full id.
Let me know what happens.
If you are getting the mail that you sent, that means the mail sending is working and something is wrong in the mail of your friend.
Don't forget to click the ACCEPT button so I get paid for my work.
Which mail service are you using ?
Did you try removing and adding back the mail account ?
There is some change in the settings it seems
Let me know what are the settings that you have given.
for the Ntlworld in iPad
I think it better to remove the current account and add it back
What are the pop and smtp settings ?
Try the above settings.
This is the settings
So you have to delete the present account and add it again back with this settings.
I will opt out and invite another expert for this.