On Sat, 25 Mar 2017 12:03:06 +0000, F news@nowhere wrote:

It looks as though I'm going to have to thread a thin, so very flexible,
cable into the ceiling void from below and then out again a couple of
metres further across. I've used a straightened coat hanger in similar
circumstances before but the current stock won't straighten to the
required distance.

I have used the top section of an old fishing rod in the past.