Wenham, a former UK police officer, said she and her friend Barry Doyle, who was driving, were headed to a bridge night in Cherrywood when she glanced down a driveway.
"I've been told I'm quite nosey as I like looking down driveways. As we were driving along I just happened to glance down David and Sylvia's driveway and suddenly saw a pair of feet sticking out from under some bushes," she said.
"I told Barry to do a U-turn and we went back to check if someone may have fallen over and sure enough it was Sylvia partly slumped over her in the front garden," she said.
Wenham said Sylvia Lawrence was quite lucid at first but she couldn't sit up on her own and she began deteriorating "quite quickly".
"Sylvia was struggling to communicate, feeling very cold, shaky and throwing up, and I was quite concerned. I got Barry to immediately ring 111.
"While we waited for the ambulance I got a duvet for her and reassured her and David, who was clearly also in shock, that things would be okay, " she said.
Barry Doyle said he was "just the driver" and let Wenham take charge as she was the one with the paramedic skills.
"I have elderly parents myself and just did what we could until the ambulance arrived."
David Lawrence said he was still "amazed' that his ill wife had been spotted and insisted that their rescuers' first aid efforts were like "some kind of miracle".
"It is nothing anyone else would not have done in the circumstances, and being a former police officer my training just kicked in," Wenham said.
"I was in my element bossing the other three around," she quipped.
Sylvia Lawrence said she was still feeling a bit of shocked and not able to stand for long.
"But I am so thankful to both Jo and Barry. They're miracle workers to us."
