I also run an IT service provider in the UK, specialising in providing assistance to organisations that cannot afford, or justify the expense of in-house expertise. I have a number of clients running XenServer 7.1 and am looking to switch them over to XCP-ng as soon as is practical.
I am a software developer myself, and whilst I generally don't work with Microsoft products, I have been playing around with the XCP Centre build and have a version up and running. It seems to work just fine. If anyone needs any help building it for themselves, I can probably assist (though the project does seem to have a maintainer already??).
Happy to help out with coding, testing, documentation etc.