Hi client has an underground car park not totally enclosed, concrete ceiling no open penetrations, fire doors to stairs to office accommodation above. There is a sprinkler system fitted and only a manual call point installed. I would have expected to see some smoke detection installed as if there was a fire with no one was around to operate the call point then it lacks any early warning until the sprinkler activates?

That is compliant - BS5839 allows sprinklers to be used as heat detection plus if you put smoke detectors in a car par they would go off all the time - usually where detection is added it's point heat or linear heat cable although you could, depending on the type of system, use a multi sensor such as the Discovery Optical/Heat in response mode 4 (less sensitive) but you don't gain too much plus the car parks, being usually open plan even where enclosed, don't usually warrant the speed of smoke detection as people would quickly be aware of an incident developing.