I found changing my time zone on my Echo simple but I could not get my address changed to a UK address. This meant that if I wanted the weather or local info I would ahve to add the phrase “in Slough England” to my questions. I found the below guide and gave it another try. Using the guide I was able to change my address to a working UK address. Now if I say “Alexa where am I?” she tells me that I am in Slough. If I ask for weather reports they are now for Slough UK and if I ask for a chinese takeout she finds my local ones.
Take a look at the below link and give it a try. https://devdiner.com/internet-of-things/how-do-i-set-up-an-amazon-echo-in-australia