Mansfield Leather Sherwood Cup Competition

I found this certificate when going through my dad’s belongings. It’s a certificate awarded to dad’s uncle Frank (undated) who was a skilled boot maker/illustrator. Uncle Frank sadly passed away in 1968 so it obviously predates that. I also have some items that Frank made. He not only made shoes but also illustrated the soles (and uppers?) for exhibitions etc. The other two photos I’ve included here show a plaque featuring a self portrait and the other a tiny boot “paper weight” or maybe child’s toy. Does anyone have any more information regarding the Sherwood Cup Competition????