I’ve been able to add the instruments that are for sale currently to drop-down menus, so those pages are accessible again. This is not the best way to navigate the site, and as soon as I can get help or figure out myself how to restore the old layout I will do it. I apologize for the inconvenience of using the site now, and the (I hope temporary) absence of the archives of sold instruments from the instrument pages.
I hope that normality will be restored relatively soon, but between my lack of coding and other computer skills and the lack of engagement from my hosting company it looks like it might be a while. The good news is that the instruments themselves are not affected by the tribulations of all these seething masses of electrons.