Well since I started this thread, I thought I would jump back in and make a comment. After all the positive feedback from everyone, I now have my 280SL insured by Hagerty (underwritten by Essentia) through my local insurance agent. I was very pleased to learn that my local agent was able to offer me coverage through Hagerty at the levels of liability coverage that fits my needs, and still have an existing umbrella coverage be tied to the vehicle insured through Hagerty.
Thanks to everyone who jumped in and offered their opinions and experiences.
Jim