The good news is that Thunderbird is no longer timing out on me when trying to connect to the mail server at moments-lost so *hopefully* that means the rest of the server issues will be resolved soon.
(42,000 words.... most of it is - as we say in this part of the world - shite, but dude! 42,000! Plus, the basic story is still rocking my socks!)
eta see? Knew as soon as I posted it would be sorted.
Sorry for bothering you - normal service has now resumed.