UK Building Insurance for overseas landlords

[Whatapantomime]

We live overseas and own a property in UK. My Mum lives in it. We need building insurance. Brokers I’ve contacted are requesting details of a managing agent.
We visit and maintain the property regularly (probably more regularly than an agent would) We don’t want/ need a managing agent.
Can anyone in a similar situation recommend a provider they have used without having a managing agent in place?
Thanks

Slightly different situation, we were overseas and the property was empty, but Howdens were very helpful. We also used them when the flat was tenanted but we did have an agent then.