Buying a house with a new roof that hasnt been approved

Hiya, we are in the process of buying a 1970's detatched house thats had a new roof, but our solicitor has just informed us that the property has not had planning approval for the new roof, and asked me what i wanted to do, she said it could or could not be a problem, and said i could take out an indemnity if i wanted, what does that even mean?
We only had a specific survey done on a wall that was cracked on the property, but not a full survey of the house, would i be best informing the council and seeing what they say?
I think the roof was replaced about thee or four years ago, and it was tiles replaced with tiles
Thanks for any advice