I have the main P9 in the living room, then a satallite slave unit in my study upstairs and then finally a third satallite unit in a garden room about 20m from the house.

I can get really reliable WiFi from the Garden Room unit which gets it's signal from the Stuady that in turn gets it's signal from the main unit. However when I work in the study right next to that second unit I have all sorts of WiFi speed issues and work video calls (particularly upload connection) are really bad.

I have the main unitl connected to a Virgin Media Hub router. I've tried rebooting the router and resting the Decos, and also fully power cycling everything. I've also tried two different devices in the study and have experienced the same problems.

To me it makes no sense as it's fine in the garden room and that's connecting via the study so I don't understand why theres so many issues in the study. 

All thoughts and suggestions welcomed please as it's driving me mad.

Thanks