Bella's arrival in Hong Kong earlier this year marked the expansion and growing acceptance of the guide dogs scheme in the city, which resumed three years ago.

The service, which aims to provide more independence and freedom to the visually impaired, was introduced in the 1970s, in Hong Kong with two dogs called Opal and Winta. But when the dogs died in 1979 and 1981, they were not replaced, and the service was shelved.

That all changed in 2011 with the arrival of Google, a Labrador pup donated by the Taiwan Guide Dog Association. Google went on to become Hong Kong's first guide dog of the 21st century.

Today, there are only eight trained guide dogs matched with owners in the city. All have been provided by two charities - the Hong Kong Seeing Eye Dog Services and the Hong Kong Guide Dogs Association - after being donated by similar organisations overseas.

Both charities are now stepping up their services by bringing in more puppies, training new instructors and establishing their own dog breeding programmes.

There is a strong demand, according to the Guide Dogs Association director of business development and training Brian Francis. The city has around 122,600 visually impaired people.

"It is estimated only 1 per cent of visually impaired are likely to have a dog which would make 1,200 potential users in Hong Kong," says Francis.

This makes extending their service by breeding their own dogs a crucial part of the mission of both charities.

Key to the breeding programme's success, says Francis, are volunteers, like Lily Lam, who foster the puppies for the first year of their lives before they return to the associations to start their full training.

Lam, like all the volunteers, underwent a series of interviews and checks before she was allowed to take Bella home when the dog was just five months old.

She is one of six people who have recently taken in newly arrived puppies for the the Guide Dogs Association. The Seeing Eye Dog Services has nine puppies with foster parents.

"The puppies will stay until they are about 14 months. During that time we ask that in many ways they are treated like normal pets," Francis says. "That means they need to be taught good manners, be socialised, obedient, and clean in the house.

"It is also important that they are exposed to as many different environments as possible during the first year.

"They need to feel comfortable in busy street conditions, on escalators, the MTR, or on a bus … all the different environments that the user would want to go to."

That also includes the workplace. Lam, a programme manager for a software company, typically works from home. But she occasionally has to take Bella into her office, and not everyone is welcoming.

Lam sometimes encounters hostility towards Bella, even when she is wearing a special coat which identifies her as a guide dog in training.

"It can be paradise, but it can also be a hellish experience taking Bella out," Lam says. "Some people really support you and understand she is a guide dog in training, and shouldn't be disturbed. Others don't understand, and ask why I am allowed to bring a dog to certain places. Usually that happens in smaller businesses or restaurants, and I have to try to explain.

"But Bella is a smart dog. She is very receptive to the way I feel, fast at picking up things, and willing to learn from me."

The lack of public understanding means that education plays a big role in the associations' work, says Francis.

Both charities rely on sponsors and donations. Each new dog costs the charity around HK$300,000 to bring in, train, and keep healthy during its working lifetime, says Francis.

Half of the dogs fail to make the grade. "If a dog is taken out of the programme, it is usually for physical reasons or because of its temperament. It may fear large trucks, or the MTR," he says.

When that happens, they explore other options, such as having the dogs provide comfort as a buddy in a home for children or the elderly. If that isn't possible, they ensure that the puppy will go to a good home.

The Guide Dogs Association will begin breeding its own puppies next year with the arrival of two brood bitches from established breeders overseas. The Seeing Eye Dog Services hopes to start sooner, and has already identified two of their own dogs as potential breeders. It's an exciting time for the group, says Raymond Cheung Wai-man, a founder member.

Mei and Mike Liu know exactly how easy it is to become attached to one of the dogs, having recently returned foster puppy Billy to the seeing eye dog services after seven months.

"Of course, we will be extremely sad to see him go. Billy is like one of the family," Mei says, just before bidding the puppy goodbye.

"But we knew what we were getting into when we joined the programme. We know he will go on to do great things for a worthy cause. We will be very proud if one day we see him on the street as a seeing eye dog, leading his owner."

Lam believes she will learn a lot personally from her time with Bella, too.

"It's very meaningful to be a puppy raiser, though I am still not sure how I will deal with saying goodbye. We have connected in the time we have spent together," Lam says.

"I like to think when people see how well behaved Bella is, she is not just promoting the guide dogs programme, she is also helping raise the status of pets in Hong Kong."