Normally you do not inform the fire service as most unwanted attendances to fire drills are the result of Alarm Receiving Centre calls resulting from your panel's remote monitoring link. Few systems are linked directly to fire service controls and even fewer have autodiallers and continous reel message tapes.
Prior to a drill we will take a system off watch with the Receiving Centre so they will not call the brigade & if the procedure has designated persons to dial 999 on alarm signal only (i.e. before confirmation of fire) they are told of the exact time of the drill & not to call 999.
The only embarrassing incident of the fire service turning up to a drill I've had was to my first ever one many years ago. i asked the managing agent's surveyor if there was an ARC link or autodialler - he said no; the key people in the tenancies had prior knowledge, yet a couple of minutes into the drill two pumps turn up. Red faced I explained it was only a drill & asked how they were called - they stated an ARC had called them. Perplexed by this I then noticed the adjacent property seemed to have evacuated as well. Upon questioning people from this building it transpired that although my building's IP had no ARC link, it did in fact have a relay to the adjacent buildings panel which did. Sadly my buildings agent, who should have a good knowledge of the premises didn't even know it. To worsen the day the call point used to activate the drill promptly failed and stuck in FIRE condition and I couldn't reset the system and had to wait three hours for an emergency call out engineer to come and fit a new call point........
Brigades have had different approaches, but they are all supposed to be adopting the CACFOA guidance on monitored alarms, which brings policy in line with the ACPO guide for security alarms, where a single false alarm will bring a ticking off, but a history of false alarms will rsult in a progressively lesser response until they will not respond to a call inititated by the fire alarm, but only to a person making a 999 call of a confirmed fire.