Anyone know of a standalone flame detector ?

I know they exist for cigarettes providing a recorded message, however
I want one which screams its head off.

A relative just left a tea towel on an electric hob. Despite
interlinked smoke alarms AND a heat alarm in the kitchen, the only
evidence of the event was a tar stained cooker hood grease filter (on)
and a pile of ash on the hob.

A simple UV? flame detector would have shrieked its head off (no
smokers, electric hob). Ok it rules out the usual "flamed cooking",
but I'm surprised one doesn't exist somewhere. Google doesn't show
anything apart from the cig-arrete type.