I would recommend the tyre insurance. These run flats are pretty expensive and from past experience you only need about 2 claims to pay for it. I've claimed about £4,000 in tyres from my last 2 policies. Each tyre on my 3 series was about £350. Not sure what the 1 series tyres cost but I'm sure I'll find out in time.
Ps. You never heard it from me but if your tyres are running low on tread a couple of nails usually let you claim lovely new ones.