After getting answers from the following question:
I have been able to reconfigure my old BT Home Hub 4 as a Wireless Access Point and I have also purchased a WiFi extender. On the home layout diagram (attached to previous question) the HH4 is in the back room downstairs and the WiFi extender is in the back room upstairs. The primary purpose of the WiFi extender is to provide a wired connection to the PVR in our bedroom; mainly for firmware updates but also hoping to be able to read the contents of the PVR drive over the network but that will be the topic of another question.
However, the purpose of this question is because since doing this setup one of the family is now complaining that there are occasions when he gets no WiFi signal to his games console (X Box One) in his bedroom whereas he did before.
In his room he should be in range of all three sources of WiFi, in order of proximity:
1) WiFi Extender - configured to same SSID as Hub 5
2) HH4 - SSID Hub4
3) HH5 - SSID Hub5
Is it possible that he is getting too much WiFi signal? He isn't dropping connection which would suggest he is hopping between devices, he just can't see them when scanning for WiFi signal.
Would this be a network issue or an issue with his console? I suspect it is the console but wanted to rule out any network issues that may have been caused.