Foreign body in RX100iii viewfinder

My problem is a foreign body, probably an eyelash by the look of it inside the RX100iii viewfinder (which is the same as the one in the RX100IV). It seems to be just inside the rear glass which magnifies it. However I can see no obvious means of removing the rear of the viewfinder or its casing.

Is there a downloadable service repair manual available for the RX100iii, failing which the IV