Hi PPP
This might be a useful place to start looking:
http://www.mister-auto.com/moteur-de-ventilateur/renault-4-112-1-1-34ch_v1971_g792.html
Or, if still unavailable:
https://www.amazon.co.uk/Valeo-Service-698004-Fan-Motor/dp/B0068NM0GK
Or for a secondhand unit:
http://www.palace-de-lancienne.com/products/moto-ventilateur-de-refroidissement-pour-moteur-cleon/
They're usually very robust units and work reliably for years, although I have known them to seize. The problems normally come with the sensor and/or connections.
I managed to get a fan and motor complete from my local scrappers for €25 thanks for advice.Thanks
I will check all connections but it looked like it was starting to seize in the summer.
Thank you.