Sorry Mattias, when I copied the rbm scripts from "c:\program files\KLayout (64bit)" to the new location, the were marked as hidden so KLayout did not see them. I should stick to Linux.
OK I found this works:
lbl = cell.shapes(layer_index).insert(RBA::Text::new("hello",Trans::new(10000,1000)))
is this the correct format. It does work but just seems a bit messy to me!