It meant the next stop yesterday in Johnston's afternoon distributing Christmas cheer was the hospital's children's ward.
''I think it is absolutely brilliant and thumbs up for Toyworld for doing something like this,'' Riley said. ''It's just lovely when two kids have had such a tough time.''
Zahnee, 12, was born with Phaces Syndrome, one of only 400 people in the world to have this complex medical condition. A mark of the syndrome was a facial vascular haemangioma tumour that grew on and under the skin on her face.
The pleasure of getting the presents was written all over the faces of Zahnee and her 11-year-old brother who has autism.
''This is awesome, I can't believe it,'' Zahnee said.
The children freely give their time fundraising for the Salvation Army and the SPCA. They play a big part in their mother's dog sitting service for family and friends and operate a little business on the side bathing and blow-waving dogs while their owners were at the shops. They take a little pocket money with most of their earnings going to buy food for the SPCA.
The children volunteer for the SPCA and the Salvation Army and assist the Sallies with leaflet drops, foodbank collections and the Red Shield Appeal.
Riley said if everybody did their bit, the community would be much richer. Her own strong social beliefs were mirrored in her children who she wants to grow up to have strong morals and compassion for those worse off than themselves.
Zahnee, who published a fundraising book in 2012 called Zahnee's Story, Achieving my Dream, said the best part of the surprise visit was finding out that the hospital would get something out of it.
Riley said they felt privileged to be chosen for the gifts because there were so many other deserving families.
The arrival of Santa Johnston yesterday topped off an exciting lead-up to Christmas that has featured a special needs children's picnic and the Riding for Disabled party.
Riley said there had been so many tears this year that it was lovely to come to Christmas and have a bit of a break.