I got a reply from UA last night regarding the 'rumour' that Sonar support has been dropped.
Of course, it hasn't. UA has taken the (I'm guessing economical) stance that they will fully test on a few hosts. They went on to say that their plugs should work in any DAW that supports the VST protocol.
And, once again, their service staff were nothing but pleasant and cheery. I love those guys.