On 17/09/2018 21:21, Brian Reay wrote:

There are different types, at least 3, of detectors which are
recommended for different rooms/areas for just the reasons you say.
Placing the right one in the right location/checking it has been done is
the kind of thing I'd expect a competent Building Inspector to be able
to do. May be a call to the local council?

Your local FPO would be a better source of advice.

--
Spike