So the final update to the thread is that I have a clear answer that the home is unserviceable. Disappointing, but at least there is closure to the enquiry. None of this would have got anywhere if it wasn't for David_Bn of the forum team chasing this internally.
The gaping chasm of standards between the wholly inept customer services and the forum team (with the latter seemingly the only people who can get things done) is frankly stunning in this day and age, so it's perhaps a lucky escape. Thanks again to David, without whom none of this would have been resolved.
