"Calling" company (4)
I believe the answer is:
avon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">calling company</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for avon that I've seen before include "English river flowing through Stratford" , "River joining Bath with Bristol" , "Shakespeare is know as the Bard of . . . ." , "English river, flows through Stratford" , "River flowing through Bristol to the Severn" .)