There's a Engelbert Clever Nachfolger(Successor) thread here: http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=260927&page=1 . The successor(I'd guess a son-in-law or it could be someone that purchased the firm) sourced the Belgian craftsmen of Liege for this Herold example, which is Franz Jaeger's patent. He was a firearms merchant and peddled some interesting and unique sporting arms. Maybe PeteM can narrow the date with the diameters but I'd guess after 1910 and before 1922. It has the Record trademark on the butt which goes to some Franz Jaeger-Scholberg collaboration. Note the S&D(Scholbert & Delheid(?)) monogram/trademark on the hinge pin.

Kind Regards,

Raimey
rse