I guess this puts a new meaning to.. [getting ready for the quick exit] ... "Snail Mail"
https://www.bbc.co.uk/news/articles/cm2nlym5y2jo
Mike
Flickr: Peak Rambler
"the postbox was stolen in 2023 and had to be replaced"
One could assume that the previous postbox wasn't similarly affected.
Was it replaced with a postbox that attracted mail-eating slugs?
Have they tried copper tape around the supporting post? (Supposedly it discourages slugs).
Some slugs are predators. Some slugs are detritivores.