WITH the London Marathon a distant memory it is easy to forget the charitable causes and personal stories of those who took part.

However, a Slade Green driving instructor is keeping the fundraising and sport link alive by embarking on a mammoth challenge of endurance after spending years as a couch potato.

Mark Gunnell will take part in the Blenheim Palace triathlon on May 20, followed by the Exeter triathlon on June 4 and the London to Brighton bike ride on June 18.

His gruelling challenge culminates on August 8 when Mark takes on the London Olympic triathlon.

All the money he raises will go to the Alzheimer's Society after wife Penny lost her mother, Margaret, to the disease last month.

The 36-year-old father of two said: "When Margaret was diagnosed with the disease in 1997 it really took hold of her and within three months she was a vegetable. It was like she just shut down.

"Penny would be in tears as she watched her own mother's downfall.

"We often wondered whether Margaret was aware of what was around her but when her husband, Ron, died in 2004, she wailed long and hard so she knew enough. It was harrowing."

Mark had decided on his challenge as a new year's resolution having spent 19 years on the sofa.

He said: "I thought while I am doing the challenge I could raise money at the same time and the Alzheimer's Society was the obvious choice."

The charitable drive took on greater poignancy when Margaret died on April 4, aged 66.

Mark said: "It was a blessing in disguise really as Margaret had had no life for nine years."

At Blenheim Palace, Mark, of Bridge Road, takes on the super sprint triathlon consisting of a 400m swim, a 10km bike ride and a 2.5km run.

In the Exeter triathlon, held in Tiverton, Devon, he steps up a level to the sprint triathlon 400m swimming, 24km cycling, 5km running and the London to Brighton bike ride is 58 miles of pure pedal power.

However, Mark is saving the toughest challenge until the end with the London Olympic triathlon.

Held at the ExCel Centre, Victoria Docks, the race involves swimming a mile in the Thames, cycling 40km and then running 10km.

Mark said: "I'm not looking forward to how cold the water is. I did an open water swim over Easter and it was painfully cold.

"Your hands, feet and face get so bad it feels like you cannot breathe and are suffocating.

"And, as all the swimmers go at once, I am a little worried about getting kicked in the head."

Mark's training is going well and he has a rigid weekly routine including 10 to 15 miles on his bike, 70 lengths at Erith Swimming Pool and 10km runs.

He said: "I had been quite slow on my mountain bike and so have bought a new racing bike which I think will improve my training even more."

Sponsorship is going well with added support from Mark's accountants SK Thakrar & Co. Ltd as well as grocers ABC Brothers.

If you want to sponsor Mark on his quest, visit justgiving.com/sponsortheelephant