For what it's worth, I had my main Q box swapped last week, support was great but it took a couple of attempts.
I called when the box was coming up with an intermittent "technical fault" message on all boxes that would last around 10 seconds and then back to normal. I use a wired connection between boxes, the first person I spoke with (after being in a queue for around 1 hour (understandable given the current climate) the guy that answered was working from home!). He asked me to change the Wi-Fi channel (36 to 40) even though I explained it was a wired connection (apparently it can still have an impact, first I've heard of it?). I also pointed out that it was the main box also having issues and was not through on demand content, if it were just the mini boxes then network connectivity would be an obvious issue. The advice I was given was to move all boxes away from anything that would create electrical noise (already done) and when the fault happens again to turn off my router and then all Sky boxes even if I'm watching content coming in via the dish - I did point out that the internet connection was stable and that I wasn't willing to turn my router off and back on again due to sync speed SNR issues - as it was my Sky connection speed apparently would not be compromised(!).
A few days later the technical fault error returned and stayed on, I rebooted boxes, 12 hours later the fault was still present. I phoned the Sky helpline and explained the whole situation again, the person was familiar with the fault and couldn't understand why the previous person had given that advice as it was clearly a fault with the main box. I explained I was happy to do a self install if they could get me the box, an engineer was in the area, he called him (with me on hold) to see if he had a spare box he could drop off, the answer was yes and the engineer would be in contact shortly. 1 hour later the engineer called to say he was 10 minutes away, I took out the old box, and exchanged for the new. He scanned the barcode on the cardboard box to link that box with my account. I had to set the box up on another TV, which made the process simpler as it had a mini box on it already and wired network connectivity simplified things further (much to his delight), he checked everything, going through the menu through the window, once it was all working, remote linked and mini box connected he said it was all good to go and I could move the box to another room. I have cabled the house so connecting to the dish wasn't an issue from either room.
Just goes to show how customer service levels can vary hugely, as I suppose is the same across all industries. The wait times, an inconvenience but it is the same everywhere right now and anyone who complains about that is incredibly narrow minded.