By Sally Nancarrow
BBC News, Surrey
On Easter Monday, a 17th Century mansion in Surrey will be the scene of a traditional spring fair, complete with egg hunt and bonnet competition.
Eight-year-old James is recovering at Tadworth after a brain tumour
Also over the holiday, a local gardener is opening her gates to visitors and selling hot cross buns and coffee.
Small events - but they are part of a huge drive by little-known charity, The Children's Trust, to raise £7.2m.
Its home, Tadworth Court, near Epsom was once a country offshoot of Great
Ormond Street Hospital.
Now it is the UK's only intensive rehabilitation unit for children with brain injuries.
It helps 250 children a year, from all over the country, to regain a quality of life after an illness or accident has left them with catastrophic brain damage.
For example, two-year-old Ollie's brain was deprived of oxygen when he choked on a grape. Afterwards, he could no longer walk, eat, sit up or hold a toy.
Sports-mad Alfie was 10 when he was knocked off his bike. He was in a coma for 72 hours and in intensive care for three months.
Afterwards, he could not walk, talk or feed himself.
Eight-year-old James is at Tadworth to rebuild his life after surgery for a brain tumour left him with an acquired brain injury.
The Children's Trust also helps children who have profound and multiple learning difficulties from birth.
It has 75 children in its care at one time, but is building accommodation for 22 more - which is where the fundraising comes in.
The music therapy room is typical of the new child-friendly facilities
Children are referred to Tadworth by their doctors, and the NHS pays for their places, which can cost more than £1,000 a night.
It covers their basic needs, but the extra provision which staff at Tadworth believe makes it such a special place has to be funded on top.
Currently it is building new residential accommodation for children such as Ollie, Alfie and James, with a flat where their families can stay.
The 40-year-old hydrotherapy pool is also being replaced.
"We have raised about £4m so far in about a year and a half," said Oonagh Goodman, senior fundraising manager.
"We didn't get planning permission until last year and grant-making bodies will not give money until you have planning permission.
"The work will be finished next year - and we have to pay the builders by then."
The largest donations received so far are about £1m from the ACT Foundation and £500,000 from the Garfield Weston Foundation.
Justin with his nurse Cristina, gets on with enjoying childhood
But Ms Goodman said events such as the Easter bonnet competitions and hot cross bun sales were equally valued.
"We had a school that grew vegetables and then sold them and raised about £16," she said.
"At one of the local schools, the children were sponsored for running round the playing field and raised something like £2,000.
"Small events raise quite a lot when it all adds up."
The Children's Trust is not the only Surrey organisation trying to raise millions.
A few miles away, at Headley Court, they are building a £5m gym and swimming pool to help rehabilitate wounded service men and women.
Both are up against huge, well-known charities such as Cancer Research and Macmillan Nurses.
The Children's Trust has been unable to apply for National Lottery funding because it does not fit the Lotto's criteria.
It has now set up its own lottery, with 2,500 players paying £1 a week.
There are more than 400 staff at Tadworth Court, including nurses, physiotherapists, social workers and housekeepers.
The charity was set up in 1984 to run Tadworth independently of Great Ormond Street.
Since then, all the old hospital wards have been pulled down.
The new therapy centres and residential units are light, modern and spacious and it is no longer a hospital, but a home from home, where the business of being a child comes first.
The new buildings include rooms specially designed for physiotherapy
That is important for children like five-year-old Justin. He is a real character but is dependent long-term on artificial ventilation, is in a wheelchair, and needs 24-hour care.
In the New Cheyne Centre, James is being taught science in a one-to-one session in a bright, airy classroom.
His teacher, Peter Dalton, demonstrates how water moves up the stem of a plant and James examines the specimen under a microscope with great interest and concentration.
Ollie made remarkable progress during his stay at Tadworth, learning to chat and move around until he was able to return home, in his parents' words, "a transformed child".
Alfie regained his speech and memory at Tadworth and learned to walk again - now he is training to run the London Marathon in aid of the Children's Trust.