I replaced the front mount OEM antenna on my 1965 1800 with a flush mount electric one. The reasoning was that the original antenna was a grabber (and I mean that seriously). If you leave your car unattended people just love to see how much spring and how far the antenna will twang. This causes more damage to the fender than the antenna, and you'll not only have to repair the fender you'll have to replace the antenna. Usually your insurance deductable is succh that it won't cover the cost. Besides when you put your car cover on at night you have to fiddle and try to get the antenna through the hole in the cover. You do have a cover don't you?
If you replace with an electric version, most antennas available now have a hook up to the radio, so when the radio is turned on the antenna goes up. Your original Bendix radio doesn't have this feature. So find one that is an older manual switch type and put the switch under the dash.
As far as the radio, I looked at the new ones and decided to stay with the orig AM. I think it looks better.
What type of mirrors do you think were on the car? Mine were Talbot and were mounted on the front fenders. If you are thinking about mounting on the fenders let me know and I'll measure mine for you if you want, or send an e-mail picture.
I'm Havinfun