"He asked her to leave her husband Robert and her children and move in with him this month, but she refused and ended their relationship," the Daily Mail reported.
Police warned Bailey not to harass Mrs Downes, but he approached her in the street and pulled her hair.
"I became terrified of him,' she told the court. "He wanted to see me but when he got me trapped in an alleyway I became frightened and started to scream.
"I thought he could have a knife. All I could think of was my Charlene and what happened to her. I had toescape."
Bailey' s occupation was listed on court documents as a restaurant worker, and he was described as living in guesthouses in Blackpool, in north-west England.
He was fined 75 ($151) and given a six-month restraining order after pleading guilty to the assault.
The Daily Mail reported Bailey had a seven-month relationship with Mrs Downes, but she denied it had a sexual element.
After the hearing, Mrs Downes told reporters the relationship began through a website she had set up as part of her efforts to solve her daughter's disappearance.
"He had shown an interest in my website - the Charlene case - and it snowballed from there," she said.
"When he told me he was coming over here, I thought it would not happen. I was surprised when he arrived. He wanted me to leave my family and control me, but that was never going to happen."
Bailey's lawyer, Gary McAnulty, said his client believed he and Mrs Downes were in a serious romantic relationship, and he had moved from New Zealand to be with her.
"It was slightly bizarre because Mrs Downes is married and lives with her husband," the lawyer said.
"After being warned by police, he arranged to meet her to discuss matters and said he loved her.
"I have had to explain to him she wants nothing more to do with him. It is a sad end."
A Ministry of Foreign Affairs spokeswoman said Bailey had not approached the New Zealand High Commission in London for consular assistance.