Help with assessing housing renovation costs

Hi all. I am starting to approach the housing ladder as a first time buyer. I have zero experience when it comes to housing. I have found an interesting property for sale here in Cambridge, however, it requires full renovation. I have no idea of how much the renovation would cost and this determines whether I can afford it or not. The estate agent did provide an estimate but I am speculating that they are biased towards the lower end (please correct me if I am wrong). Is there an independent professional here in Cambridge who comes along at house viewings and helps unexperienced buyers? Is this a thing? How would you do it? I'm not looking for an expensive in depth surveyor, just someone who knows about the current housing market, building materials cost etc. who could give me an estimate of any additional cost required.

Any suggestion/tip will be appreciated.