Thank you@pmroz for the instructions. Very useful with some particularly dirty data.
If anyone else needs a handy example try the following:
If(
Regex( :"2nd"n, "^[A-Z]+$" ) == :"2nd"n, "Uppercase",
Regex( :"2nd"n, "^[a-z]+$" ) == :"2nd"n, "Lowercase",
Regex( :"2nd"n, "^[0-9]+$" ) == :"2nd"n, "Numbers",
Regex( :"2nd"n, "^[A-Z0-9]+$" ) == :"2nd"n, "Uppercase and numbers",
Regex( :"2nd"n, "^[a-z0-9]+$" ) == :"2nd"n, "lowercase and numbers",
Regex( :"2nd"n, "^[A-Za-z]+$" ) == :"2nd"n, "No numbers",
Regex( :"2nd"n, "^[A-Za-z0-9]+$" ) == :"2nd"n, "All characters",
Regex( :"2nd"n, "^[A-Za-z0-9]+$" ) != :"2nd"n,
"includes non alphanumeric characters"
)