A brief history of Japanese comic works in the UK
Once upon a time, there was some manga-influenced work being published in the UK. They were mainly illustrations in magazines though, not so much in comic format. I put this timeframe down to a pre-internet era of the mid-90's in video games magazines, especially with the rise and fall of TokyoPop in the early to mid 2000s. TokyoPop ran an annual competition ("Rising Stars of Manga") in the USA and UK/Ireland for a number of years, but it has not ran since 2008 so it's not an option any more. SuperPlay and other games magazines were champions of showcasing Japanese video game artwork originally. Now, Viz Media have launched a new initiative (see “Self-Publishing”). The doors are opening.
From the 90's to this present day, people have always, always published their own Japanese-inspired comics and printed works. Though fewer people make fanzines (fan-made magazines with news articles in them, etc), people are still making comics, merchandise and illustrations, and you can support them via online shops, in Comic Villages or at comic events around the country. The ones I am going to personally are listed on my website.
Authors who make their own comics usually also sell them online, check some out via Etsy or Comicsy if you can't make it to an event.
Nothing has really changed from this format in the last twenty years for people who make their own, alternative, home-produced, Japanese-influenced comics in the UK, so for now that's just the way it is - until there is a demand, and a sustainable creative market. So do support what we've got with your purses and wallets to create supply and demand at events and online!