"having walked" is correct and usable in written English.
You can use it when describing an action that's already been completed. For example: "Having walked around the park, I was so relaxed."
It's just that, having walked round the Tate Britain show, I can't fully understand it.
He left after six innings and 92 pitches, having walked one and struck out four.
Seven years later, he found himself at Prudhoe Bay, in Alaska, having walked 19,019 miles.
After having walked seven kilometers (4.3 miles) with the group, Ms. Venkatesh said, she was tired.
Their father died after having walked himself to the hospital, after a heart attack.
A few minutes later, having walked back to the house, we said our goodbyes.
Still more people arrived throughout the night, having walked from Serbia.
He allowed only one walk, after having walked 10 in those previous two starts.
Inside were four Spanish monks who, having walked to Rome on pilgrimage, were driving back.
He once admitted to being jealous of Neil Armstrong for having walked on the moon.
The tired-happy exhilaration of being a mile high having walked there.
