I drive quite a lot on single track roads in Scotland (i.e. entire road width can only handle one vehicle at a time) and I don't think I've ever encountered any

I drive quite a lot on single track roads in Scotland (i.e. entire road width can only handle one vehicle at a time) and I don't think I've ever encountered anyone using their horn like that. At a blind corner, you just drive slowly - no uncivilised horn usage.