By Caroline Wyatt
Defence correspondent, BBC News
Pte Lee wants to return to his comrades in Afghanistan
Private Johnathan Lee is learning how to walk again.
His face is concentrated, his back ram-rod straight as he grips the bars either side of him, determined to balance on his new prosthetic leg, fitted just four days ago.
The lower half of his right leg was so badly damaged below the knee by a landmine in Afghanistan last November that it had to be amputated.
Now all the 25-year-old's energy and concentration is focused on putting one foot in front of the other, and learning a new way of balancing to stay upright.
"It is painful,” he admits as he finishes the morning's rehabilitation session at one of Headley Court's gyms.
“You've got to get over that pain and you've got to walk in it. You can't give up, because then you might as well just go home. There's no point being here if you're not willing to work hard."
Pte Lee's vehicle ran over the mine as he was on the way to deliver supplies to a frontline base in Helmand province.
Originally an Elizabethan farmhouse
Was the HQ for Canadian forces in WWII
Bought after WWII following public appeal
Now Defence Services Medical Rehabilitation Centre
It took two long hours before the de-miners and medical help were able to reach his convoy from the main British military base at Camp Bastion.
In the meantime, he injected himself with morphine to deaden the pain until help could reach him and his colleagues from the 2nd Battalion the Yorkshire Regiment.
Yet today, his one ambition is to return to Afghanistan when he has finished his rehabilitation at Headley Court.
“I feel I let them down by coming home early. It's quite strange to think that, I know, but I just want to get back there in 2009 to try to redeem myself by completing a full tour.” And he gives a rare smile.
'I owe it something'
Pte Lee has taken hope from men such as Sergeant Stuart Pearson, from the 3rd Battalion the Parachute regiment.
Sgt Pearson is now back at work in the regimental shop at Colchester, despite losing the whole of his leg in Afghanistan to a landmine in 2006.
He is at Headley Court for follow-up treatment, and is currently training for a 340-mile bike ride for the charity Help for Heroes.
Sgt Pearson is determined to be fit again
It is trying to raise £8m for a new swimming pool for Headley Court, as patients currently have to use the local public pool in Leatherhead. So far, the public has raised £3m.
“I'm trying to run and get myself on the bike as much as I can, to train for the Battlefield Bike Ride in May,” he says, adjusting his prosthetic leg so it is at the correct angle for pedalling.
“I'm determined to do it because the Help for Heroes charity is doing so much for Headley Court, and I got so much out of Headley Court that I feel I owe something to it."
But should charity, rather than the government, be paying for a facility so clearly needed for Britain's wounded servicemen and women? Sgt Pearson and the others will not be drawn on that.
The commanding officer, Wing Commander Steven Beaumont, insists Headley Court gets the budget it needs.
"We do get good funding,” he says. “We had the 30-bed ward annexe built last year, we've got the accommodation planned for this year, so there is money there and support from the government for what we do.”
At the moment, Headley Court is 80% full. The majority of patients being treated here are those who have been injured in motor accidents or other incidents.
Only 26 of the current in-patients are those very seriously or seriously injured in the conflicts in Iraq or Afghanistan.
Among them is Lance Bombardier Ben Parkinson, who is back for further rehabilitation after being able to spend his first Christmas back at home.
In the prosthetic limb workshop downstairs, staffed by six RAF technicians and an NHS expert in prosthetics, are a new set of legs for Ben Parkinson.
“We have a lot more challenges in our work here. The average NHS patient needing a new limb is aged 65 or above,” says prosthetist Ian Jones.
“These are young men who want to be active again, to go across country, doing sports, running and cycling, and that's driving the development of prosthetics.
Aims to return injured personnel to full physical and psychological fitness
Hosts unique Limb Fitting and Amputee Centre
Specialises in orthopaedic, head, brain, sports and spinal injuries
200 medical and support staff work at Headley Court
"Their new legs also have to be able to bear the extra weight of a backpack and sometimes a weapon.”
As the patients upstairs get ready for their daily warm-up exercises in the main gym, those with legs amputated below the knee are teased for simply having a "scratch", admits Sgt Pearson, with a wicked grin.
The 32-year-old has never done a 340-mile cycle ride in his life. Now he hopes to complete one with a prosthetic leg.
The men here are determined to battle their way back to fitness, and - for Pte Lee - perhaps even back to the front line.