My car was written off. I've agreed to buy a new one, delivery originally expected on Monday 2nd, now delayed at least two weeks.

Dealer is going to put me into one of their cars until my new one arrives. Asked me to cover it on my insurance and pass expense on. My insurer can't because I don't have a policy until new car arrives, and won't let me put a dealer's car on my policy and start it from Monday.

Dealer seems to have a problem with covering me on their insurance, including my using their car for work. Any advice about what to do?