@Glen_King
With regards to a motorised skylight. I am planning to do a loft conversion and as part of that to fit some Velux windows. Velux already do motors for them and use the io-HomeControl system to control them. They have also partnered with Netatmo to do an Apple HomeKit system meaning you can then use Siri to control them. https://www.netatmo.com/en-GB/partners/velux
I believe some people have come up with other methods of linking to Velux, this some times involves adding your own relays to the motors, or getting your own bridge to io-HomeControl - possibly a Somfy TahomA. Apparently the TahomA box can link to both RTS and io-HomeControl, however you might need to do some work to get a suitable device handler for this. See TaHoma® by Somfy and https://www.somfy.co.uk/products/1811541/tahoma-
If all your worried about is a sensor to confirm it is open or shut and not to control the window then a standard door/window magnetic sensor will do the job I would have thought including the Smartthings one - https://www.samsung.com/uk/smartthings/sensors-plug-f-mlt-uk-v2/F-MLT-UK-V2/