"I was hoping to have been there [for the High Court trial]," he said.
He said the sentence was not enough but he understood the judge's process.
"I would love to see him locked up forever. [The judge] has done it to the letter of the law as much as he could; he gave him as much as he could."
He said O'Reilly had maintained a stout denial of his crimes throughout.
"As far has he's concerned, he seem to think he's got the power over everybody, to brainwash them to think the way he thinks."
Mr Gardiner said when he went to trial, it was for him, but more victims surfaced. He went on to help police help others, he said.
"Now I can close this, now that we know he's away for seven years. At least the system has changed enough so that these people do end up going away for a long time."
Mr Gardiner says he does not want to be involved any more.