try using What3Words

I have heard of it, a laudable concept - let us hope it will gain traction. It has the potential because Post Codes vary from country to country, and Zipcodes (AFAIK) have an even coarser resolution. What3Word has a resolution 3 metres BTW, and there are duplicate locations, albeit distant from each other. And it is proprietary.

But in practical usage it requires the "event" organiser to know What3Words AND use it. The kind of things I am talking about are events in Village Halls. These events (see map.mister.red ) are organised by people who don't all see the relevance of a Post Code in publicity, or even who the artists are sometimes.

And car SatNavs are for worldwide use so the default grid is LatLong, not UK OSGR - which is not that user friendly even though they are good enough for all but Geocachers.