Hot again today but below 30C so I was able to repair the steel frame of the forward-facing, bulkhead-mounted large vestibule window by welding in a new strip along the bottom.  This had rotted due to its contact with the aluminium beading that runs horizontally below the two windows on the front bulkhead.  Hopefully I shall be able finish preparing the window and paint it tomorrow.

Window frame in process of being stripped

Close-up of welded repair to window frame.