hi @Morgan_Hardwood, so I didn’t read the page properly! 
I’ve now compiled a Dev build and it all seemed to work ok, leading to RT launching, except for one glitch. On doing “~/rt/rawtherapee” I got this error message six times in quick succession in the Terminal window -
(rawtherapee:15448): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion ‘size >= 0’ failed in GtkScrollbar
Do I need to worry about this please?