ISP Support relied:
I have sent a test message and can see that the sent email does in fact fall into sent objects folder instead of the sent folder. I have escalated this to our 3rd line support team to investigate. As soon as we have an update we will inform you via this ticket.
Your patience is appreciated while we aim to resolve your issue.
Is this progress? If you recall, they originally suggested there was no issue!
I wrote back (and here use 'iHope' where appropriate):
Thanks for your message and testing.
Your test confirms something important. When a message is sent from your end it appears (correctly) in the 'sent objects' folder. When a message is sent from my end it appears in a sub folder of Inbox, called 'sent'. The two versions are mirroring each other in a strange way!
The connectivity issue of 2 April appears to have changed the folder structure in Webmail and my email client application. When normal connectivity returned Webmail and my email client did not revert to their previous the folder structures. That's the problem.
On 5 April I wrote to you describing what happened in my email client as follows:
"When the Webmail connectivity issue occurred on 2 April the Sent mailbox disappeared from the Mail application on my computer. The application (by itself) then created a new Sent mail as a sub-folder of something it named "@iHope". All the sent messages are in this new Sent sub-folder.
When the Webmail connectivity issue was cleared up the Mail application did not revert to its previous condition, and would not allow me to create a new Sent mailbox.
Today I sent an email, the first since this issue began, and the Mail application itself created a new Sent mailbox in the same place as before (and with the correct symbol). This new Sent mailbox contains just that one message.
I should like to transfer all the other sent messages (currently in the sub-folder of "@iHope") to the correct Sent mailbox, so things are back to the way they were.
However my Webmail account on your server presents a different picture. The email I sent today appears in a newly created sub-folder of INBOX, called "Sent". And all the previous mail sent is still in "Sent objects" - although in my computer's Mail application they're not in the right place."
I hope my description of 5 April clarifies what the issue is and helps in finding a solution.
iHope