Thanks for yesterdays reply Alan,
Your assessment of the cause of the problems makes sense even to me.
Although AirNav eventually sorted out the Data Update problem more than 10 weeks after they were informed about it in July, they were also informed about the other problems at the same time, so it strikes me that when you get the type of 'Not Us Guv' response from Support that Nigel received in his opening post, and the standard automated reply Ian got in post 21 in the Metars thread, it's a waste of time any more of us contacting them about it.
I have though sent them an email asking that they sort things out, and also clarify the situation by way of a response to R/Box users in general through this (their) forum, even though as you said, they very rarely bother to post on here.
Syd.