Warrantywise have quoted me £603 for a year or ~£900 for 2 yrs. The coverage is more comprehensive than BMW and no £5k limit. The excess I used was £50 and the labour is for the car to go to BMW. With regards to servicing, only genuine parts and adherence to the scheduled maintenance have to kept so one can take the car to an indy.
BMW don't cover oil leaks on their warranty either!