I run a company that installs C-Bus in Greece 5 years now.
The problem that we have to confront, and becomes bigger as time passes, is the integration with the HVAC installation. New HVAC installations have a lot of temperature and humidity sensors, plenty of control zones, and a pump room really nightmare for humble systems like C-Bus.
The best solution is to install a BMS system and integrate it to C-Bus. For this purpose Bacnet Gateway and OPC Server and offered from Clipsal but are not available for UK.

So, I was wondering if there is someone else than me that would be interested for these systems. My company would use probably 1 or 2 of these per year....