Had the same issue a few years ago …only thing I could find was….not sure if the 12v one is still available, the 240 one will need mains power but it does have a relay to connect to the alarm
Kitchen is showing 2 in that screen shot ….how far is kitchen from alarm panel ? Move kitchen pir near control panel see if the issue stops …if so it’s a wireless signal issue
Follow the same numbers that are inprinted in the old handset …
Blue …with white ………6
White with blue …………2
Orange with white ………1
White with orange ………4
Green with white…………5
White with green ………..3
Twin and earth to first smoke ….brown L blue N …..then 3 core and earth ( grey interlink ) brown L ….Black N
They could have sleeved the black with some blue sleeving…pretty straight forward …