Yes his set up is fairly new. But BA is on objects like rocks glass, decor, filter parts... It creeps as well as gets spread by the water. A UV will help slow it from spreading, but a UV can't stop BA. Eventually it should just go away. You can wipe it off and like I said, it should have a harder time coming back each time with a UV. I have had GREAT luck with BA (and GA) by using semaprochilodus species (fei fengs) They seriously have always obliterated any algae stuck to stuff. I've never had any luck with plecos helping algae.
Also, the effectiveness of your UV is determined by the water flow through it, it's design and the intensity of the bulb. I have a cheap jebo 36w that can only be a UV "STERILIZER" if I run it at 150 or so gph. While my 9w TWIST (the twist helps to maximize exposure to the UV) coralife can sterilize at 350 or so. If you run either faster than that, then they are no longer sterilizers and they become clarifiers. It becomes a clarifier since the water is running by too quickly to get enough exposure to kill as much as it could if the water was moving..
The other thing of course with BA is that the rocks and objects that the algae is on doesn't run through the piece of equiptment.