It's not just the Cat 1 hold that may affect you.
For example at EGCC during LVP safeguards sections of the permiter road are also closed off to prevent vehicles straying into an area which may affect things.
It's not that uncommon for practice auto-lands to be carried out but you really should let ATC know what you're doing.
They will then let you know the status ... i.e. OK but protection is not in place.