How do I verify which breed my dog is? (For insurance document)

Hi all, I adopted a dog from a rescue three months ago. (My first dog!) I was told she was a Terrier. From googling it I think she is a Patterdale Terrier. I haven’t met others like her on our walks. I’ve asked at two different vets and they are reluctant to assign her a specific breed and called her a Terrier. They guessed she was about 2 years old.

People I’ve talked to on our walks have told me they’ve used online companies to find out the breed. Can you recommend any?

Recently my husband took out pet insurance for her with Allianz and guessed when answering breed type (purebred / crossbreed / mixed breed) and breed as we just don’t know for sure. (I wondered if choosing purebred would mean more costly insurance... Maybe I’m better off not knowing?!) My husband put her down as a ‘Patterdale Terrier cross’ (selected from the list provided) and ‘Mixed breed’ (“an indeterminate breed”) and now I’m fretting about how we should have answered this question. I feel silly saying it, but I’m well aware that insurance companies can be troublesome about claims, and the cost would change depending on my choice, and we don’t know the correct answer! Should I ask them to update the details to just call her a Terrier, as is on her microchipping cert? Thanks for any feedback.