Insurance HELP

The Boise group now owns a towplane, not what we wanted to do but...
Would like to know where other towplane owners are getting insurance
for the plane besides Costello??
We are looking for glider/banner towing and instruction insurance but
are interested in knowing who people insure with even if only for
towing gliders or instruction. Please respond directly to my email
and I would appreciate the information as soon as possible. Please
include the name of the insurance company, phone number and the
broker's or agent's name you deal with.

Thank you for any assistance.
Tom
Idaho