iMessage conversations not showing

Hello All

I have one of these:

Just done a 10.13.3 update, admittedly with some issues so I ended up doing a clean install. Everything works great except my conversations are not appearing in my iMessage Application. They have disappeared. The conversations are still there on my other other devices and I am able to send and receive messages as normal.

I have turned iCloud off and on, preferences look as they always have:

I have looked at the Library file and the database seems intact, its a fair size too with all the picture attachments.

I am not sure what the "incompatible chat db" file is so I even removed it and tried but still nothing.

I am at a bit of a loss, I have tried renaming the Messages folder to MessagesXXX as seen in previous community threads. I have tried removing preferences too. I am able to send and receive messages from all the accounts I just cannot see any previous conversations. I have also reset PRAM and NVRAM and I have done an SMC reset.

Any help gratefully received!

Many thanks in advance

Richard Butcher