The HX50 is *not* a kit helicopter. Admittedly I only have experience with the FAA and not the UK CAA, but to give a real (in the US) example, five years ago I bought a gyroplane from a US manufacturer, and at the time all two-seat gyros in the US had to be registered as 'experimental' and officially 51% owner-built, but factory assist was allowed at least in practice, so the manufacturer just had all US-based owners go to the factory for a couple of weeks to help assemble it and that was that. I know Magni (Italian manufacturer) offered a similar program; you flew to Italy, helped build your gyro in two weeks, then flew back home and they ship your completed gyro to you.
Building an aircraft from a kit takes years, even 10 years if you have a job, but the factory-assist thing is a loophole allowing you to do zero manufacturing and basically just help assemble it. And, in the US, you only need to show you did 51% of the work if you want to do your own annuals, which only a fool would do IMO.