Hi Richard
I was diagnosed in August 2017. I started with Michael Mosley's 8 Week Blood Sugar Diet, that is 800 calories per day, but from info on here and watching Jason Fung on Youtube I also went low carb (20g per day) with 16:8 IF.
My hba1c went from 106 to 35 in 4 months, I lost about 20lbs in the initial 8 weeks. I went on to lose 5 stone. Over the last 26 months my HBA1c results have stayed in the normal range, and so many other health markers have improved - cholesterol, BP, fatty liver etc and I feel fantastic. I don't know about long-term safety - I'm a bit of a data geek so I'll be continuing to monitor things anyway - but so far for me it's worked brilliantly.