Your ownership history is a potential concern, to be sure, and the agent may have placed the risk with Lloyd's because no domestic market was willing to take on the policy. As far as price, I can't say, as I don't have all the facts....
If you have the coverage ready to go, I'd say put it into place and get your vessel insured. Get some experience on your boat, don't have any losses, and shop the policy before the renewal. Experience will be your best friend in getting the lowest premium possible.
Peter- Marine Insurance Guru & tuna fishing addict!
1989 52' PT Overseas yachtfisher