Sigh it seems that 52 has broken several extensions one of them was Conversations which was allowed me to see threading emails including my replies interspersed in with the received emails.

If you have an issue with an addon then you need to inform the author of the addon as it is their job to make sure their addon products continue to work with Thunderbird. It is not the job of Thunderbird to work with addons, but the other way around.

Conversations Addon: https://addons.mozilla.org/en-GB/thunderbird/addon/gmail-conversation-view/

There is a section discussing version compatibility.