I bought tickets via the O2 priority app.
I've not only had my money back but they also refunded ALL of the fees.
As someone else said, it must be something really serious to not just cancel some of the tour, but things as far as 18 months into the future.
Could be his mum to be honest. His mum has been the main focus of a lot of his material and as we all know even named a previous tour after her "Mum want's a Bungalow Tour".
We can't claim he cares about his mum anymore than we care/have cared for our own but we can claim he cares about his mum the most. I'm pretty sure it's related to that.