Since 2012, Selco employees and suppliers have raised more than £120,000 for Macmillan and this year have pledged to raise an additional £50,000.
Ms Cooper was joined in the event by fiancé Paul Gemmell.
"It was a tough course, with two very demanding hills, but it was a great experience and I’m delighted to have completed it," said Ms Cooper.
Selco has already raised more than £20,000 so far this year. Other fundraising initiatives planned for the year include charity golf days, a 100-mile coastal cycle challenge, a nominated charity match at Selco-sponsored rugby Super League side London Broncos and participation in the national Macmillan Coffee Morning.
