I really would'nt lose sleep over it, my BMW is 7 years old, and, has supposedly covered a mere 104k from new, I have detailed history of the car, but, thb it all means very little imo. I'm pretty certain my car is "genuine", but, who really knows?
I would'nt know if it had actually done 200k! - Its got a digital odometer that any numpty with a laptop can alter to his hearts content, and service records are easily reproduced and I've seen stupid mileage cars that really don't show it at all ,my old man has an e39 5 Series, just passing 200k you'd think it had done less than 70k to look - closely - at it.
BTW, I paid £5k plus my old car for my BMW.
I don't lose sleep over it and for what you've paid mate, you certainly should'nt.