Heather says they were lucky that the daycare the girls attended also placed an importance on swimming and were happy to take the children down to swimming lessons during the day, which helped.
The girls each moved on to more formal swimming lessons at 4 or 5, taking part in the Swim2XL programme run out of Lynmore School.
Aside from that, she says swimming is also about enjoyment. The girls both love the water, she says.
"They enjoy the water, but they've also got a lot of respect for the water."
She says knowing the girls have had swimming lessons allows her to feel more confident when they're around the water.