Same experience for my - as Ivormog says, the mileage is still recorded when you use the car, so is accurate when the LCD comes back on.
I now have 2 small electric ‘greenhouse’ heaters that I have from late-Autumn through to late-Spring: one of them is positioned just under the dashboard on top of the gearbox housing to keep everything dry (the 2nd one is on the garage floor under the engine👌).
These are plugged into the extension lead that is in place all year-round for the battery conditioner, so that I know they’re on when they should be.
