How do I reset Geolocation settings please?

Hi Everyone,

When I initially started using this brilliant site, I declined to let the site know my location. 

However, now it would be really useful if I could use the mapping tool feature: 'use current location', but as I initially declined to let the site know my location, I can't currently use this when route planning. 

How do I reset my geolocation settings and say 'Yes' to the site having access to my current location?

With thanks to the community for any help offered, Georgia