In short, friends of mine had fibre installed and are having issues with wifi. Only the cellphones keep dropping the wifi connection (and often wont connect back up) on the ultra hub (both apple and andriod) - all other devices such as laptops and tablets that connect via wifi are not seeing any issues.
Vodafone has replaced the hub but the same issues occur (there were other issues with the first hub as well).
I have checked and manually changed the wifi channels to ensure other nearby networks are not causing any issues/interefence/on the shame channel.
They were on VDSL before that with an ultra hub and did not have any issues.
Any suggestions on what to do next?