Whilst I applaud the sentiment, this demonstrates one of the flaws with crowdsourced data (I presume).

The result list for me (that goes as far as 7.5 miles away) shows 'unknown' for every garage, which therefore renders the list useless. No doubt it would improve as more users offered up information, but unless there is a way to automate the data the majority of more rural areas (perhaps even anywhere that is not a large city centre) will never find any use for this.