Welcome, keep reading, the bentley is apparently very good and comes with good mods to the movement to get the seconds to 3 oclock, but keep reading and hold on to your money for a while and only when you have made a good consious descion then buy, there is so much to choise from.
You have a shiny ring with 4 cutouts on it, on the inside of this ring you have flats that when aligned with the flats on the bearing will allow the rotor to be removed, i had a small problem with my AT with the seagull where the retaining ring turned its self and the rotor fell off !, i got it back on no problems with a couple of screw drivers, i am sure that there is a special tool with 4 prongs to do this a lot easyer.
Well if you swapped out the movement you might as well send the crystal for either Cheiftang or K2222 depending on where you are for double AR, you mat well be very close to the price for the ETA one with AR with postage and what have you. With the supply being a bit dry at the moment of the ETA one nmaking it your self may be the ony option.
Sorry to here that it is beyond repair, it really is a beutiful watch, is there no way of fixing it, although if Ziggy says that hope is lost then RIP, sorry for your loss.