Cable avoiding tool cat3 use?

Hi, I want to demolish an old outbuilding, do a site scrape and dig some footings for a new building. I think it is likely that mains services pass nearby so I am looking at hss hire of a £50 day cat3 hire. Is this doable as I,ve never used one before and it looks fun to do?! I had a misspent youth treasure hunting with a metal detector.