How to remove B&W 800 N midrange??

I am pretty sure the driver is blown and would like to remove it to test/replace. It looks like the midrange driver is held in by a threaded rod that goes through to the rear of the enclosure. Does anyone know for sure? I am the second owner, so there is no warrantee to be concerned with. Thanks.
You need to acquire from the nearest dealer or the B&W service center the rod that screws into the center of the midrange driver once the bullet is removed. Step one , remove grill and center bullet. Step two, screw rod into center of midrange driver, hand tight is fine, Step three, acquire a friend to help. Step four, have the assistant hold the rod from the front of speaker such that it will remain stable as you unscrew the screw from the back of the marlin head. The transport screw. The assistant needs to have a stable hand as there is a jel substance that interfaces between the driver and the marlin head that you want to keep undisturbed. Once the screw is removed from the rear, the driver will be free with the exception of the connecting wires. Unclip wires and pull foward. A few things to note. The screw is a soft material and will probably be marred up with a screwdriver. The rubber washer that surrounds the screw in the rear is good for one application. You may want to order a screw and washer when ordering the long rod. The procedure is not difficult btu requires care and patients.
Unscrew the long rod from the back, hold the driver from the front while doing so as it will eventually "fall out".

Use a very large screw driver or something as wide as the slot, or it will leave mark on the "screw".

It's not rocket science, I have done it on 802N.
Don't have a direct answer, but I had to replace a tweeter (on a much cheaper DM series spkr). When I called B&Ws US importer/service ctr in MA, they were very helpful with instructions on how to do the replacement. In fact, I also ordered a gear for my Rotel CD drawer assembly and they were instructive for that fix as well. Great service for a $30 parts order.
Arcoleo and semi.....congratulations, you know more about this than my local B&W dealer. He is looking into borrowing the 700.00 tool from B&W. What a pain! Thanks to all for your help.
Beheme,i was thinking the same thing,i would love to see a pic of this grovy device so i could replicate it & sell it for a 1,000 % discount,talk about banging the customer out at every turn.
I have a poping sound once in a while from 1 bass cabinet. not sure which driver so i ordered both to be safe. has anyone ever replaced one of these.

Yes, I replaced my mid driver according to the instructions above. Not hard at all. The problem turned out to be a fuse type device built into the crossover. B&W sent a new crossover at no cost. Problem solved. However, my speaker made no sound at all. Different from your problem.