Hi all,
February 2018 I was able to talk to one of the Spanish guest workers who settled down, married and still lives in Haren. He was the one confirming that the Klooster was inhabited by these workers until 1976.
Indeed you there is a picture dated 1973 showing the notice "Puerta de España" what means "Spain's door".
You can find that picture in one of the archives of the region under the following link:
https://www.bhic.nl/memorix/images/search/detail/5e205920-45fb-11e3-9330-573033f30800
Best regards,
Monroy