He suffered a broken back, perforated ear drums and scores of lesions, but said he would have died had it not been for the care given by two Londonderry women - Donna Patton and Grace Curry - who sat with him and gently cared for him.
Mr Leatherbarrow made an appeal through the pages of the Belfast Telegraph last month to find them. After many phone calls, we put them in touch and on Saturday they met for the first time.
Mr Leatherbarrow has taken part in a roadside service on Remembrance Day for the last two years in memory to those who died, but said he was most nervous this year, knowing he would meet the women who saved him.
He immediately recognised them as they met in the car park of the Silverbirch Hotel in Omagh.
"He laughed, probably with nerves, and then it was OK," said Ms Patton.
Mr Leatherbarrow added: "Donna hasn't changed. I recognised her immediately and said hello Donna, then I said hello Grace and she went, 'Awk God, it's James'."
He confessed that as the group of former soldiers who travelled from England met the group from the Londonderry band, he couldn't stop staring at Donna and Grace.
Both women said they had always wondered about him in the intervening 27 years, whether he had got married, after he had told them about his planned nuptials back then.
Ms Patton was just 16 years old as she looked after him that night, cradling his head on her lap and urging him to stay alive.
However, there was a note of sadness that Ms Curry's husband Kingsley, who had pulled Mr Leatherbarrow from under the bus, was not there. He passed away just last year.
Ms Curry presented Mr Leatherbarrow with a Remembrance teddy bear, complete with uniform and poppy as well as a special glass keepsake. Mr Leatherbarrow's jacket had been stuffed with teddies from a coin-operated machine on the night he was blown up.
People who lived close to the site of the bomb in Ballygawley on August 20, 1988, and helped on the night, including GP Clifford McCord and UUP councillor Allan Rainey, also met up in Omagh on Saturday.
Eight soldiers, aged from 18 to 21, died in the IRA blast. However there were some survivors, including Mr Leatherbarrow who thanked all those who took part in the rescue effort for saving his life.
"If it were not for you here, I would not have what I have today, I would not be alive," he said. "Thank you for saving my life."
He said the day had been brilliant, after the initial nerves, adding he thinks it helps the post traumatic stress disorder (PTSD) he has suffered since the bomb.
"As soon as I walked in I recognised them. You know when you have that good feeling? I just can't stop looking at them," he said.
"It is sad, though, that Grace's husband isn't here - he pulled me from the wreckage.
"It was mainly Donna who nursed me on her lap. All I wanted to do was go to sleep but she would not let me. I kept saying please don't let me die, and she didn't."
He said back in the 1980s there was no help for those with PTSD, unlike now. "It was all just self-help basically, but seeing all these people has been like a friend and I feel it helps the PTSD," he said.
"These people are heroes to me. They see us as heroes, but we were just doing our job. We were getting paid to be here, but they are heroes."
Ms Patton said the initial request to meet Mr Leatherbarrow again had brought back a lot of tough memories.
"We never spoke about it after, I have never even talked about it with my husband," she said.
"I thought long and hard about coming today, I thought it might be too emotional.
"I had felt very bitter for many years. The band did a parade on the Shankill Road after the bomb. We were cheered, but that was the last time I ever marched, I had just had enough.
"But I had always wondered about James over the years, how he was, whether had got married.
"We are strangers even though we have this horrific connection. It was a bit surreal, but he put us at ease straight away with that laugh. I hope he has found some peace."