Marshmallow 6.0.1 I think, I took my phone in for repairs on Saturday.
The O2 shop said it was a known issue but Sony hadn't advised them further either. My phone was in warranty until the end of this month luckily. I'll report back once I get my phone back.
I strongly suspect a software issue. There are reports of the same issue from all over the world from people with phones of all ages, I don;t think it could be a hardware fault for that many devices just after an update, it's too much of a coincidence.
Marshmallow 6.0.1 I think, I took my phone in for repairs on Saturday.
The O2 shop said it was a known issue but Sony hadn't advised them further either. My phone was in warranty until the end of this month luckily. I'll report back once I get my phone back.