In all the many years of using BT, I've never used BT Email as my main email client.
I've always used Microsoft Outlook and used BT Email as a backup method only.
That way I can have the luxury of a properly designed email client and if anything happens, I am covered as my emails are still stored on BT servers.
Not trying to knock BT's own web email client, however everybody will have their own personal user preferences and some will be happy and think BT's is adequate for them, whilst others will want more etc and therefore go for a proper email client like Outlook or Thunderbird as mentioned previously, others are available too!
The only thing I do every so often is to log into BT Email and check spam folders to make sure that nothing is stuck in there that should have come through etc.
I do agree with your reasoning of being able to delete more than 200 at a time, along with a simple popup window with a checkbox that the user has to click to confirm that they want to delete all their emails for example.
Not that hard to implement something like that, then it is the users responsibility if they delete all emails and not BT as they have been made aware and still proceeded.
Other companies have done that and require a checkbox to be ticked to clear all the folders contents, so nothing stopping BT doing it too.
As you mention 18k emails, if you went say Outlook route instead, then you have you got additional settings that you can tick to occur like delete mail from server after so many days or delete from server when deleted etc.
Even simple things like that would clean up a lot of emails for you.
I also run Outlook as POP3 accounts too even though most nowadays will try to push you always down the IMAP route, so that anything I do there doesn't affect BT servers and emails stored, thus not affecting any backups needed
You could simply run as IMAP and anything you do through Outlook or any other client, would simply sync with BT servers.
See here:
https://www.bt.com/help/email/manage-email-account/manual-settings/what-are-the-settings-for-outgoin...
I also use a third party plugin for Outlook to save and back up my emails through the pst files that Outlook saves too on a daily basis once closed, onto a seperate external drive, which gives me a backup to Outlook first, before having to go back into BT Email for anything.
Finally, is it intentionally done the way you have turned your question about BT Email into an advertisement for the company you have mentioned?
I do not subscribe, so please do not always expect a reply.
