Hi Lesley
Don’t worry, it’s still quite early, yet for the hogs to return from hibernation, especially the females. I have found, here, that the female hoglets seem to stay in the area, but the males tend to move on elsewhere. So it depends a bit whether the hoglets were male or female. Hopefully one or some will eventually make their way back.
In general, the way to encourage hogs to visit your garden is to make it as hog friendly as possible. There are some ideas in this link https://www.hedgehogstreet.org/help-hedgehogs/helpful-garden-features/ That will encourage the hogs natural food, but you could also offer some supplementary food, i.e. cat/dog/hog food. Also water is very important and best offered all day every day. Fairly large but shallow plant saucers are ideal for water.
Good luck, I hope you have some hog sightings soon.
