Development of new binding: Drayton miGenie

Please can someone advise at top level what is involved in development of a binding for OpenHAB and where I can read-up about this area?
I’m very pleased with the new central heating and hot water controls from Drayton that my plumber has retro-fitted for me. We’re soon to also benefit from commissioning the underfloor heating in our new extension too.
Unfortunately there is not (yet) a binding for this system available for OpenHAB2: I spoke to the manufacturer before I went ahead and they said they don’t plan to make the protocol open source for this generation but I decided to proceed anyway due to other reasons, the main one being that it’s a really good system in every other way.
I love OpenHAB and the functionality available from my linux server deployment that I have put together for someone else’s Nest, and I am considering embarking on developing a binding for miGenie myself because I would love to integrate wireless TRVs with it and have more control and feedback from the system.
I realise that this is a step up from what I have done before, which really only amounts to configuration of the server and the OpenHAB application, but I like a challenge! I’m not aware of any legal restrictions preventing this.
My other question is: Should I hack into the local hub that connects to my router, try to emulate the app on my mobile, or fit a wireless dongle to my Rasperry-Pi and install a local OpenHAB server there to control the hub in parallel to the user interface modules that come with the system. I suspect the last option would be the most successful.
Here is a link to the manufacturer’s product page for my system: