Do it yourself!
So "Manga" or "comics" terminology aside - there are benefits to both self-publishing and being published. Many artists just really love Japanese-style comics so they make their OWN books. While there is a lot more marketing and advertising involved with this method, any money you pay goes directly to the artist to support them… no publisher money-cut!
If you wish to go this route, I'd say the first step is to locate the type of comics you want to make, and they can be bought by people who self-publish (published individually, or published as a group). Learn from what's being made already. There are numerous comics/anime/game events that run up and down the country now, so it's best to check out the Comic Village sections of such events to see what people are making, and work on making your own version!
Once you have drawn your comic (manually or digitally), you will need to make a digital file ready for printing it with. This is the bridge between your pages and a final book. A guide to making PDFs for your comic is listed here. Obviously use specific UK publishing sizes (A4, A5 etc) if your comic requires it!
Finding a good publisher is user-specific trial and error thing. Some folks use the same one each time - some folks move around and try out new ones. It's up to you, and what works for Person A may not work for Person B.
To get started, Rich at Comic Printing UK will help you get cracking regards publishing issues! Obviously, you will need funds (savings? Kickstarter? A monthly Patreon?) to publish your own works. There are numerous printers available in the UK, but Rich specifically helps out comic creators via email and Twitter, especially thos enew to making comics.
If you wanted, you can pitch your self-published book to a publisher or editor at a comic convention to sell your idea to a larger company. Basically I think we can all agree that receiving a box of books you have made YOURSELF is the BEST feeling ever!
Ideas for co-hosting, advertising etc
Sometimes you may just want to draw a comic without worrying if it gets published by someone else. This is great if you are suffering 'burnout'.
Maybe publish two short stories in one book with a friend's comic too? Share table costs, publishing costs and distribution responsibilities :)
You may not want to publish in print, but publish online using Tapastic, Webtoon or other comic hosting sites. Or get a WordPress site up and use a plugin (like this one, or this one) - or code a website yourself, and use adverts via a platform such as Google Ads to raise revenue (but be aware you will be currently responsible for EU VAT via VATMOSS every tax year to do so). You can do all of these options! (Do ensure your website does not take any copyrights away from you. Protect your own content.) If needed, collaborate with a talented programmer friend for assistance, or commission them to help you out.
It pays to read up on VATMOSS, but 3rd-party websites that cover the collection of EU VAT include Etsy and Patreon, so use these sites without worrying about EU VAT rate collection.
At the time of writing, how Brexit will affect UK artists’ digital income is unclear, but I will update as soon as I know more.