Before you do ANYTHING anywhere you may be seen by the public you MUST contact the police before hand to let them know you're filming with RIFS
I was on a short WWI film production, set on a beach with a replica SMLE, and the police were called, but we alerted them before we even arrived so nothing bad happened.
Film production is a valid defence so i'm sure if you directly email any supplier and can prove you're a production company they won't have a problem with it.