OK, I sort of 'fixed' it.
I was on a trip and downloaded the map for that area. When I came back, I deleted the map, but when I started the app, the map was still from the place I visited (cached somehow?).
To fix it, I turned location off, which was no problem, but then selected a favourite near my home, and then turned on location again, and it was able to find it - no crashing - as it was on a map it had, so I suspect trying to initially go to a deleted location and having location on (for somewhere else), was crashing it.
Hope this helps.