http://www.genealogysurnames.com/pages/Detailed/15826.html the above link as about the surname Wrench and somewhere in the text is written that one of the theories is that Wrench came from the Scandinavian surname Olerenshaw.
According to quite some sites, the surname Renshaw means 'from the raven forest' and
shaw is an English word with the meaning 'small forest' or alike. According to other sites Earnshaw means 'eagle forest' and this confirms the shaw part and
ren means 'raven' (Renfred, Renfrid means 'peaceful raven', for example).
The
ole part i don't know for sure, but my guess is that it means 'wool' (the Norwegian word for 'wool' is
ull ). I've checked and found one Ullerenshaw. The meaning would be 'wool raven forest' or 'woolen raven forest', which seems weird, but there are surnames Woolraven and Wolraven and Woolren in existence, although they are rare. So, this might be a possibility.