I'd have thought google would use cookies to maintain you chosen 'location'. Have you tried deleting all internet cookies, then see what it thinks location is set to afterwards? But I'm deeply suspicious of google these day. I wouldn't trust them further than I could spit, and I wouldn't be at all surprised if they were somehow setting location based upon sites that you've visited, it may earn them more cash from their advertisers.
As another example I've noticed recently, if I search (say) screwfix.com for bathroom sinks, and click on the links, then a few days later I find adverts for bathroom sinks cropping up all over the place on subsequent google ads. I assume (correct me, anybody?) that's clever(!) use of google cookies?