In the case on the Cosy 6, and I suspect Cosy 9, the temperature sensor is located on the rear lower intake of the evaporator. I find that it actually produces a more accurate reading when running to when idle.
Ah!
Heatpump body definitely coupled to a hunk of mass then. Scratch that thought about it dancing around attached by it’s rigid pipework.
It’s currently using the on board sensor at the back of the Cosy like others say. I have a 10K NTC on the northside of house which was the old weather comp sensor so I’ll switch it to that later.
We have no heating load here at the moment and won’t till way later in the year.
The DHW sensor pocket is in a very different place to my old setup hence why I am relearning how much actual water is in there 
. Running out would be me in trouble!
The senior engineer was great, I’ve not heard any updates since but it’s been the bank holiday.
I think they may address the fan itself and most likely deploy anti vibration pad.
How exactly that will work I don’t know as the footprint is substantial without mourning feet like other units.
According to octopus they are trialling mounting feet on some cosys. So will organise flexis and this new mount. 
DHW looks to be about 3.4 from cold, will charge a 300L tank to 55+ in under an hour.
That’s very quick. COP isn’t especially great though, considering the air temp at the moment. Looking at a couple of your DHW cycles, the C9 has a very different strategy to the Daikins. Daikin runs at max flow rate (25L/min) throughout, with a really tight dT, whereas your C9 ramps up to 30L/min initially and then drops off to 17L/min, giving a much wider dT. Does it have any sort of Eco mode for DHW?
C9:
Daikin 4kW (more quiet mode): (ESPAltherma)
I’ve been begging for an Eco mode, these ASHP’s love to race and overshoot.
There are settings in the manufactures menu but i’m not tinkering until they have “finished” with install.
Ultimatly the inverter drive is sat on the modbus anyway,
You’ve got access to the manu menu? 
You just pass e to a function and it validates you. 