A team of 16 from the Kent based property search firm ran, cycled, paddled, abseiled and swam across 35 miles in under 12 hours.
The team began at 8:30am paddling the length of Lake Ullswayer and completed the course in the dark 11 hours later.
Judith Storr, marketing manager at SearchFlow, and participant in the event said: “The Ultra Challenge certainly lived up to its name, putting the team through its paces on land, water and even in the air!
“As we started out, the Cumbrian weather was fairly drizzly and got worse during the day. By the time we reached the Old Man of Coniston, we were soaked through and the mists had enveloped the mountain.
Storr said the most hair-raising part of the day was a 120ft abseil which caused more than a few terrified screams.
“It’s fantastic everyone completed the course in our planned time and we had a brilliant but exhausting day,” she added.
“What’s most satisfying is that we raised over £10,000 for the Demelza Hospice, who do such important work for sick children in our area.”
Donna Wells, corporate fundraising manager at Demelza House, said: “We are truly grateful for the continued support of the staff at SearchFlow. The team’s determination to push themselves to their physical limits in order to raise vital funds for Demelza never ceases to amaze us.
“Their fundraising has been recognised by winning two awards at the Demelza Business Awards”.