Advice on sensors, please

["Old Dad Smith" <oldmistersmith@xxxxxxxx>]

I've posted a (suitably anonymous) plan of my ground floor showing my
uninformed choice of motion sensor locations 1-5 and a door contact at
6.

See http://tinyurl.com/bffpz

The blue dots are the sensors and the red lines are radiators.

Could any experts out there kindly tell me if I've made a good choice
of sensor location, please, or whether alternative positions would be
preferable. Have I got enough sensors?

Many thanks