Having previously declined to continue to support Raspbian Jessie now that Stretch has been released, I've relented and done the necessary stuff to support both at http://packages.hedgerows.org.uk/

Until a few days ago there was an error in the install script that prevented the new repository signing keys being installed properly, so even if you've previously tried to update I'd suggest that you just re-run the install script anyway.

Per the notes you'll find at http://packages.hedgerows.org.uk/, to install the updated repository, get-iplayer and its dependencies, paste this line into a terminal window:

wget http://packages.hedgerows.org.uk/raspbian/install.sh -O - | sh

If you don't want to run the install script just download a copy and pick the pieces you want from it.

Cheers,
Jon