Qmini Audio, sound and now hdmi cable issues.

[Pogit]

Ok so my Q mini has had issues for a long time but Sky don't seem to want to replace it.   It's had audio issues for a long time, then it started to not like the IR accessible remotes. (New remotes sent). But now it plays Amazon movies for a few seconds then says check and or change the HDMI cable. 
the firmwares been upgraded so I'm thinking they're trying to  notch up HDCP / anti piracy measures understandable and to be expected.   However I'm suspecting a faulty HDMI port on the box as multiple cables have been tried over many many months. 

before I call and insist on a replacement box as it's gone on long enough is any one else experiencing similar.  

To clarify I do have the mini set up to a HD RF feeder do whole house display (to as best simulate my prevent 4 SkyHD box whole house distribution system) but it's not this as it happens when connected directly to TVs and that equipment is not in the loop. 

Sky Q is finally getting near to where HD+ was so it would be a shame to have to quite Sky now after waiting so long for it to become more accessible a kin to +HD levels.