I don't have any direct experience with the UK, but in the US, the requirements were a particular resolution and certain shadow qualities and contrast qualities. I was able to home print the photos at sufficient quality level and they were accepted without issue (granted, I have some reasonably high end printers, I think I used my Celphy die-sub). I can't say for certain that the UK doesn't have more strict policies than America, but that's the only experience I have to share.
Certainly making sure you have no shadows behind you, have it properly sized (exact dimensions required), have it printed with a high contrast, proper color and high resolution matter greatly, but if you can pull that off, I wouldn't expect a problem since many of the commercial products use the same process, though some are led or laser exposed and developed photo paper, but it doesn't say it has to be that in the documentation you provided.
Additionally, here is an article specific to the UK that talks about self printing. It appears that the real world experience is a mix of success and failure. No word on if the failed attempt was a poorly done home job or not though, but people appear to have had success doing so.