After yesterdays post I have some good news. One of the hedgehogs came back the next night (18th July), after a total of no sightings for five nights.
I decided to make a barrier a little bit away from the fence on the bit I had cleared. There are some bits of wood underneath the greenery, hopefully they will rot down and become a home for some insects for the hedgehog or birds to eat in the future.
I didn't think it would work so quickly and here is the proof, please be patient.
It didn't eat much, if any of the food, I may boil an egg to tempt it.