I'm in the same boat as yourself, heading to Canada (still unsure to what's gonna happen the M3)
But,
The way I see it is just brim the tank and make sure no moisture gets in, no point in starting it if its not getting out for a good run so just leave it dead. I wouldn't be worried about the flat spot on the tyres If that's all I have to replace after years of lyin in a shed I'll be pleased :wink: