ANDREW Dymott vanished on the most ordinary of days, a family barbecue at his sister’s house at Mt Eliza, south of Melbourne.

Sometime in the early afternoon, Rachel Grace remembers, her brother said he was going to go to the shop.

She watched Andy walk down her driveway, leaving his car behind. The family would never see or hear from him again.

Mrs Grace chokes back the tears during our interview but later emails to say how good it felt to talk about Andy.

“It’s hard because my brothers and I had such a happy childhood,” she said.

“We weren’t one of those families. We’d have picnics and play in the sprinklers and have great days out at the botanical gardens. It would be so wonderful to have some of those moments back, to do it all again.

“We have gone through that day over and over in our minds, looking for clues we might have missed,” Mrs Grace told news.com.au.

“We constantly look back and question ourselves, anguishing over details and possible signs he gave, but there’s really nothing.

“There was no conflict, there was no argument before he left. There was no indication that he wasn’t going to come back.”

Almost two decades after the 26-year-old electrician’s inexplicable disappearance, his family has never stopped searching, never given up hope.

“Mum and dad still live in the same house. They didn’t want to move in case he wouldn’t be able to find them when he came home,” Mrs Grace said.

Her words echo those of Suzie Ratcliffe, founder of Leave a Light On Inc, which supports and campaigns on behalf of people with missing loved ones.

Ms Ratcliffe is the sister of 11-year-old Joanne Ratcliffe, who was abducted from Adelaide Oval along with four-year-old Kirste Gordon in 1973 in an unsolved cold case that has drawn parallels with the Beaumont children.

From the moment she disappeared, Joanne's parents would leave their porch light on to help guide the little girl home.

And like Ms Ratcliffe, Mrs Grace’s pain has not eased over the decades.

Mrs Grace’s daughter Sarah shares a birthday with her missing uncle, who will turn 46 on July 21. It is always a bitter sweet occasion.

“(My daughter) Kathleen and her cousin Christopher were lucky enough to have known Andy as children and they were very close,” she said.

“All his nieces and nephews have grown up with stories about Andy. If he turned up tomorrow they would feel like they know him.”

Mrs Grace said her brother suffered from a mental illness that was being managed by professionals but that “a couple of months before (he disappeared) there were signs he was having low points”.

“At the time we didn’t know enough about (his condition) to know what to look for,” she said.

“He would talk to us, our brother Miles and mum and dad, about it but we were conscious of not interfering too much.”

Over the years, there have been a handful of reported sightings of Andy, usually after public appeals for information, but none have been confirmed.

“At the time he went missing we had another possible sighting of Andrew living in temporary accommodation in Melbourne and my husband, brother Miles, my father and a group of (Andy’s) friends searched high and low,” Mrs Grace said.

“His closest friend’s Lisa and Christian still offer their support to mum and dad to this day and are waiting to carry on conversations with him as if no time has passed.

“There was a time when a lot of us were certain he was living among the homeless community and my father considered integrating into that community to try and find him.

“He and mum have fought so hard to get information from government bodies about facilities and services that may have been accessed by Andy but there have been so many obstacles because of privacy issues.

“Some of the hurdles we’ve faced are because the states don’t talk to each other, the original detective handling his case experienced the same hurdles and there’s no centralised national database for information or DNA sharing.”

Mrs Grace said people did not realise how easy it was to go missing in Australia. It was possible to live for years doing cash in hand work such as fruit-picking, moving from town to town and crossing states undetected.

“We will never give up hope that Andy is still out there, and that he will come back to us.”

- Andrew Dymott was last seen at a family barbecue at Mt Eliza in Victoria on January 10, 1999, aged 26. He is described as 180cm tall with brown hair and green eyes.

- Anyone with information on his whereabouts should contact CrimeStoppers on 1800 333 000 or contact his family via their Facebook page.

- If you have a family member or friend who is missing, contact Leave a Light On Inc for advice about what you can do and to receive ongoing support.