@Edent Do you know about FindMeSAR? I am the developer.
https://findmesar.com
It is an open source (via browser tools) Progressive Web App (PWA) that displays the user's coordinates and accuracy value in several formats including Ordnance Survey Grid. Each format has a different colored background.
There is no cost, no signup, no ads, no tracking, no enshitification. It is my modest gift to the world.
**Not available in any app store.** To install for offline use (iOS and Android) open the web page, tap "No" and then read the "Tips".
For anyone curious about other #Geospatial stuff I am doing, my project page is
https://mappingsupport.com
#GIS #Maps #Mapping #W3W