The 34-year-old, who is related to Sir Paul McCartney, rowed 4.3 miles and then jumped on the bike to cycle 26 miles, all on machines at the Kingfisher Leisure Centre.

Her efforts have raised around £400 for The Eye Fund, a charity set up by her aunt and uncle following the death of her cousin, Simon, from a degenerative eye disease three years ago.

"I completed the row a lot quicker than I thought even though it was a bit of a struggle in the end," said Sarah, a creative manager at Stephen Walters silks in Cornard Road, Sudbury.

"Getting on the bike was a bit of a relief because it was a bit easier but that soon became a bit of a struggle too.

"I had a lot of supporters by my side who were helping me along throughout and they kept me going. There were also a lot of people using the gym who, when they had finished their work-outs, came back to sponsor me."

Sarah completed the rowing in 37 minutes and the marathon in 91 minutes.

The Eye Fund charity was set up in October and has the backing of Sir Paul, who is the nephew of Sarah's auntie, Carol Sherry.

"It took my auntie and uncle a long while to get over the death of Simon," she said. "Now they have set up a charity to help people who are suffering from the same disease.

"Since Simon's death the whole family has got back in touch with each other and we all want to help as much as we can."

One member of the extended family who has already done his bit is Sir Paul, who gave the charity enough money to launch fundraising calendars.

Sarah intends to continue raising cash though she will be not be lining up any lung-busting charity efforts in the near future.

She said: "I will continue fundraising and am planning a craft sale but I think I will stay clear of the more strenuous events for the time being.

"I was a bit achy after finishing up and the next morning I knew I had put in some effort, but it was worth it."

You can still sponsor Sarah by visiting www.just giving.com/sarahsherry