I did it - I got myself into the healthy BMI range by the NHS calculator. It was a lovely surprise as I'd had a goal of getting to 70kgs by this weekend and last weekend I was 1.2kgs off that. Do-able but a push and a whole load of circumstances meant that it wasn't looking likely. Then yesterday morning I weighed in at 70.3, which was very cheering... and then when I plugged the figures into the calculator in the evening, back it came saying healthy BMI.
I'll post the 'how' and the 'why' another time, but this is down from 89kgs which put me into the obese category, and it has taken 2 months short of 2 years. I am not planning on changing anything at this stage as I have more to lose (and tone up) to be in the optimal position.