Hiya mate,
Thanks very much for the reply and advice. Crazy as it may sound, I'm planning to now swap the 5 Series in for a 330D xDrive F31 (Touring) which are sadly also coming with run flats. Not sure how these will fair in bad weather with the xDrive but will most likely run them down then possibly swap for a winter tyre to use all year round but its just choosing the right tyre I suppose.
Most of my miles, mainly to work are motorway miles and I don't live too far away before getting onto a main road so it should be ok even if we do have snow/ice covered roads as predicted soon this year...
I'll definitely look into the winter tyres, any idea how much yours set you back?
Cheers