Stranger and stranger, just after I posted earlier, I found that I am now receiving e-mails on my Mac.
Previous poster did say it would sort itself out in a couple of days!
But I will have another look at my iPhone as you suggest, thanks.
You do not need to delete the account if you are set up as an IMAP account and are changing the settings to an IMAP account.
Go to you phones settings > passwords & accounts > Click on the BT email account > Check it is an IMAP account then scroll down to incoming server and click on Host name then change the server to mail.btinternet.com.
Ensure your email address and password are correct then click on Advance and check SSL is selected and that authentication is password and click on the server port and change to 993 if not already populated.
Go back to the last page and then scroll down to the out going server. Click on it on the server page in Host name enter mail.btinternet.com. Ensure email address and password are correct. Scroll down and ensure Use SSL is selected authentication is shown as password. Click on server port and enter 465 if it is not already populated
This is a BT forum.
You said you had a BTYahoo email account in message 7.
There is nothing we can do to assist you with a Yahoo account. The settings given were only for BT email accounts and won't work with Yahoo. If you are having problems you should post on a Yahoo forum.
Can you confirm if you have a BTYahoo email account or is it just a Yahoo email account because they are two different things.
If it is a BTYahoo account the settings etc I have posted will work.
If it is just a Yahoo email account they won't so it is vitally important that you establish which type of account you have.
If you are not sure you should log onto your email account via browser and if you look at the top of the page and see any mention of BT it means you have a BT email account.
You do not see BT mentioned anywhere and only see Yahoo, you have a Yahoo email account.