I've been actively using a book (English in 30 days) by Sonia Brough and Carolyn Wittmann in my teaching program. I really like the course. The copy I'm using was translated from German (into Russian), but all the dialogues are voiced-over by native (British) English speakers.
In one of the lessons, a guys runs out of petrol and has "a long walk to the garage". Now - as someone who lived in the US for many years I was somewhat bewildered to find out "garage" stands for "gas station"!
Do they really use this word to mean "petrol station" in the UK these days?
I usually refer to it as a petrol station when I'm actually going there to put petrol in my car. However, if I'm just going to the little shop to buy something but not getting petrol, I normally say "I'm going to the garage to buy some biscuits".
In the days before the proliferation of convenience store/gas station combinations, a "garage" was a place where you could buy gasoline and where mechanics worked on cars. So, yes, it was one location that could be though of or referred to as either a "gas station" or a "garage."
Over time, such places evolved into convenience stores, the pumps became self-serve and the mechanics disappeared. Now auto repair is a different business entirely from retail sales of cigarettes, soda pop and gasoline.