If you're not into throwing money away ... then I'd recommend firing up a copy of Mednafen on your PC and downloading a bunch of HuCard and ISO images to get a feel for the library.
If you do that, then you'll probably decide right at the start that it's worth spending the extra money on a Japanese DUO/DUO-R so that you can play the CD games, too.
Since you're UK-based, you probably don't have the emotional-attachment to the USA TurboGrafx releases that most folks here do, and would be quite happy to collect/buy the Japanese library, just like us UK PCE owners did back-in-the-day.
Then if you don't want/need to collect the USA TurboGrafx HuCard releases, you don't even need a region-modified system, as you can run all the USA HuCard releases on a TurboEverdrive.
Both US and Japanese CD releases will work on the Japanese DUO without a region-mod.
You'll probably want a Turbo Everdrive anyway at some point if you want to run any of the (small) number of fan-translated Japanese HuCards, or play-without-buying some of the stupidly-expensive "rare" HuCards.
P.S. I like the name ... it's good to see someone that remembers the classic old games!