https://www.thunderbird.net/en-GB/
A little light reading for you ☺☺
Backstory first:-
I used to have Microsoft Office 2003 Outlook as my email client until a Windows update completely borked it and Microsoft wasn't interested in fixing it. I have quite a few emails either coming or going and use 4 email addresses myself (don't ask and no I'm not a scammer).
Someone suggested I try Thunderbird and I believe Buenchico likes it. So, I installed it for a 'trial run'. Once you start adding an email address it will find all the settings it needs to connect, all you need to add is your password. I have an ntlworld email account as well.
Any emails under your account will be retrieved including those left on the ntlworld server under your name. If your WLMail was set up to delete emails once downloaded previously then unfortunately they are probably gone.
I've used it now for about six months with no issues whatsoever, even though I found the answer to get Office 2003 Outlook to work again. Thunderbird is easier and is always kept up to date.
Go on, try it, nothing to lose ☺☺☺