"A couple of weeks ago I went to the chemist and two elderly ladies started patting him. I said 'can you not pat him, he's working'.
"Then I told Lochie to find the door. They [the elderly ladies] started saying 'find the door, find the door'. Lochie didn't know what to do.
"So the woman working at the chemist said 'that's the door' to Lochie. We left and he tried to cross the road without stopping. He was completely disoriented.
"So now we have learned to stop for a minute or two, and get our breath back before resuming. He's also getting corrective training, which has helped."
Guide dog mobility Instructor Sarah Jewitt has made Lochie a fluoro orange sign, which is affixed to the harness handle.
"Please don't distract me I'm working", it states.
"I used to get people stopping Lochie at least three times a week before the sign, but now that number has reduced," Marsh said.
"But people still need to be more aware."
Marsh suffers from retinitis pigmentosa (RP), which is a group of rare, genetic disorders involving a breakdown and loss of cells in the retina.
Common symptoms include difficulty seeing at night and a loss of peripheral vision.
There is no known cure or effective treatment.
"I lost all my vision late last year, and I'd been waiting to get Lochie for more than two years," Marsh said.
"Before I got Lochie I didn't feel safe using a cane because it could cause havoc, didn't want to go out anywhere, I was pretty much house-bound.
"It was all getting way too scary."
Marsh started losing his vision when he was in his early 20s, and he didn't think he would lose all his sight.
He got his first guide dog in his mid-30s when his vision was "getting quite bad".
"I used to live in Wellington, and the dog would help me get on buses, trains," he said.
"The dog retired. I got the second one when I was knocking on my 40s and when I was made redundant from the company I worked for in Porirua.
"The second one died, quite painfully and horribly, from cancer."
Losing both dogs knocked Marsh for a six, for "quite a bit" and he wasn't up to getting another guide dog.
"Then my eyes started to deteriorate really badly, and the Blind Foundation urged me to get another dog."
That's when he applied for and got Lochie.
"Lochie is fairly young, he's just turned 2. All I can say is he's changed my life, and my wife would agree with that," he said.
"He is so onto it, he slows me down if there is a bumper on the road.
"He has given me independence, he's marvellous. I don't know how many times he has saved my life, but I'd say a dozen times at least."
Jewittsaid every dog was trained keeping a "lot" of factors in mind, with speed, size and environment being the big ones.
"The speed is an important factor because you don't want a guide dog who is faster or slower than the client," she said.
"In terms of size, Mike is fairly tall and he would look silly with a dog that's barely knee-high.
"The size would also impact the dog's ability to guide the client. Lochie fits somewhere in between."
She said the goal was to establish a working relationship between the client and the dog.
Distractions like the public interfering with a handler and dog don't help, she said.
"Dogs are social beings, distracting the dog can lead to accidents," she said.
"It's potentially dangerous, and there is no need for the public to do that. It puts off the client's orientation, and people can walk into obstacles.
"You can't teach dogs to ignore people - it's a frustrating and annoying problem."
She advises people to "not engage, not interfere and definitely not feed" a guide dog.
"And if they need to, they should ask."
Help to support the work done by the Blind Low Vision NZ [formerly Blind Foundation] by donating to the Blind Week street collection from October 16 to 17.
