I have a client who purchased another business which has mediocre reviews (7 total 3 are bad. score of 3.5) Should we mark the business as closed and start a new GBP? Address and phone will be the same and its the same type of business.
I wouldn't. The age of the listing has local SEO value, so it would suck to start from scratch.
I would just respond to all of those negative reviews, apologize for their previous experience, and let them know that you're under new ownership now and have a commitment to quality.
Then I would fire up a great review acquisition strategy to get tons of positive reviews streaming in. Once they have 30+ great reviews under the new ownership and those old reviews are clearly for the old business, then you'll be looking great in the search results.
New advertising option:
A review of your product or service posted by a Sterling Sky employee. This will also be shared on the Sterling Sky & LSF Twitter accounts, our Facebook group, LinkedIn, and both newsletters.