A little internet sleuthing and the Internet Archive Wayback Machine has some answers, it looks like they closed up shop this year. This snapshot from February 2025 states "We’re closed, thank you for 29 great years". https://web.archive.org/web/20250210064458/https://audiowaveshifi.com/
According to some of the public records sites, Alan is 71 so it sounds like he probably retired and dipped out quietly.