Not always easy to record, Brydo, unless you’re obsessive about it. Pure mode is easier because once the battery is depleted, it switches to Hybrid mode, but you have to be watching for when it happens. In Hybrid mode, the engine will kick in when it needs to so actual battery mileage very much depends on conditions. The only way to know is drive in a way to avoid the engine starting (by watching the display) and keep driving until it will no longer run on battery, then note the mileage. Or, of course if you have a known journey on the limits of the range.
The main reason for getting the car, aside from memory seats and rear camera which our X1 didn’t have, was quietness and ease of driving around town, and comfort, with the bonus of preheating and conditioning on winter mornings before MrsWs commute (I’ve yet to see how that turns out, of course). So it seems as though we will be saving on running costs too, which wasn’t a deciding factor.