Surprisingly for this relatively odd cocoa percentage there's a decent amount of choice of find chocolate. Potomac make a great Upala bar, then there's Kuna, Grenada Chocolate Company, Zotter, Blanxart.
If you were just exploring this level in the UK then I'd certainly give Grenada and Zotter a try first as they're fantastic chocolates.
The variety of actual intensities varies widely. Just like even at the 100% level you shouldn't just think that a number is displayed on a package that it is going to be much more bitter or intense than any other number. I'd suggest also trying 85% chocolate and comparing them.