Not that I was at NAMM myself, but I was watching the Anderton’s video on boutique guitars at NAMM 2017, and noticed a UK luthier that I didn’t have on my list page. It’s AC Guitars, which is a one-man custom shop in Dumfrieshire, Scotland, and the man himself, Alan Cringean, focuses on custom bass guitars (although a recent post on his website says that he’s also making 6-string guitars under another name, Reiver Guitars).
AC Guitars makes a number of different body shapes and has lots of gorgeous finishes. The range includes basses with anything from four to seven strings.
If you’re looking for a special bass, they seem to be well worth a look.