Here's a link to a website with an intriguing name ("Art Detective") by the Public Catalogue Foundation at The University of Glasgow who's mission is to identify works of art in art collections in the United Kingdom:
www.LostArt.de posted about Art Detective here.Art Detective aims to improve knowledge of the UK’s public art collection. It is a free-to-use online network that connects public art collections with members of the public and providers of specialist knowledge. Art Detective Launched in March 2014, Art Detective comprises a digital network built on top of the Public Catalogue Foundation’s (PCF) existing art object database. Art Detective is accessed through the Your Paintings website and the PCF website.