HI guys, thanks for the feedback, I should have said the presence sensors are Samsung ones keyfobs not mobile phone, and may be it’s just coincidence - but I always notice after she has stayed and it’s always OK in between.
However I did some fault diagnosis this afternoon and saw that the reason I was losing devices randomly was the routers were dropping the connection to the hub - so all direct connection device were fine but for some reason the router connections were lost (but between the routers they still connected !). I’d say it looks like the encryption keys were lost so the routers could not handshake with the hub, but why ? and why could they all talk to each other ? - and seemingly each time she comes round.
ANd yes already realigned network channels much earlier in the year in case that was causing any issues, so should be fine now they are at maximum distance.
No she doesn’t touch any of the routers I have plugged in (yes plugin zigbee module types)
Have reconnected everything and all looks good will continue to monitor.