GJ Gardner stepped in to build the couple a brand new home, which they moved in to in mid-2014.
Mr Lawton and Ms Lee laid a complaint against Mr Heron with the Real Estate Agents Authority in May last year.
The authority found him guilty of unsatisfactory conduct for failing to disclose all knowledge of a dampness problem and not disclosing a previously terminated sale agreement.
Mr Heron was not found guilty of wrongdoing around the termite infestation because the authority found there was no evidence Mr Heron could have or should have known about the problem.
The authority's complaints assessment committee released its penalty decision over Mr Heron's unsatisfactory conduct today.
Mr Lawton and Mr Lee submitted to the committee that Mr Heron had taken steps to redress the situation and no further penalty should be made.
Mr Heron had paid back the couple the commission fee from Century 21 for the sale, and also provided accommodation for the couple while their new home was built.
Mr Heron submitted to the committee that he and his family had suffered significant stress due to the media interest in the case, and asked for the decision not to be published.
The committee agreed with the submissions and ordered no penalty be made.
However, the committee said publication of the decision was in the public interest and consumers had a right to be made aware of unsatisfactory conduct.