Hi @Ruan Swart ,
Welcome to Q&A Forum!
According to my research and testing, SharePoint Column Validation cannot support such a complex RegEx Expression. Because the Validation Formula must be 1024 characters or fewer.
For example:
[A-Z]{4}- requires the following Formula:
=IF(AND(LEN(Test)=5,CODE(MID(Test,1,1))>64,CODE(MID(Test,1,1))<91,CODE(MID(Test,2,1))>64,CODE(MID(Test,2,1))<91,CODE(MID(Test,3,1))>64,CODE(MID(Test,3,1))<91,CODE(MID(Test,4,1))>64,CODE(MID(Test,4,1))<91,MID(Test,5,1)="-"),TRUE,FALSE)
Thanks,
Echo Du
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