Sony support: Day 35 (approx)
I realized I never finished the story about Sony laptop Support.
The laptop was returned after about 5 weeks, and it did work. In the mean-time some plastic is coming a bit detached around the screen (that was one of the things they replaced), but if you handle it gently, it's OK.
It was returned to the wrong place. Well I asked them to call me before they returned it, as they picked it up from one of the offices I work in, but I work in lots of different offices so I wasn't sure I was going to be in that particular office whenever they delivered it back. But of course they didn't, I just got an email from the boss of the company in the office they picked it up from, telling me it'd arrived back in that one.
Then about 2 weeks later, they called me to ask me how satisfied I was with the service, on a scale of 1 to 5. That was wonderful. I just told him everything that'd gone wrong. Then he repeated: "no sir, I need to know your satisfaction on a scale of 1 to 5". He wasn't actually interested in what'd gone wrong; he was only interested in this single metric! I also told him that I was happy to be contacted by Sony if they were interested in improving their processes. So far they haven't contacted me, so I suppose they aren't interested.