Sky Q mini connectivity

[The+Posh+Cat]

We have had Sky Q for years, and all of the boxes, the BT router, Sky extender, have all been in the same place. 

However, these last few weeks the Mini box in the conservatory has started glitching, freezing, then it will be fine for hours, then go back to glitching and sometimes goes off completely and says connectivity error message. 

I have swapped the mini boxes over from the bedroom and it is still doing it. 

I rebooted the router, main Q box, and mini, this morning but still getting the glitching. 

Any thoughts please? 

[The+Posh+Cat]

Meant to say, streaming is fine. Was watching Masterchef on Friday and it was glitching, so went to iplayer and it worked perfectly.