What is the relationship between Durex and London in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

This week's bubbly trading update reinforced this view, and allowed it to continue the 12% share price gain enjoyed during the past four weeks -- the London firm saw like-for-like sales advance 5% during January-June, with product rollouts like its Scholl Express Pedi and Durex Real Feel helping to drive shopper interest.

Answer: headquarters_location