Points noted CS, however about 100 miles away there was a cloud front which was just above our level can't tell exactly but no more than FL290 I shouldn't think as when you get closer you can guestimate with some degree of acuracy. The meteor was certainly visible below this level and this side of the front which suggests that it was a lot lower than you speculate.
If indeed it was marble sized, with its speed and temperature, I have no doubt that it would have cut a nice clean hole in my hull anyway.
Thanks for the replies, Guys 'n' gals.