I live in a row of terrace houses, although our gardens do have hedges. So I am not surprised to see a hedgehog in the city.
I would be careful about moving a hedgehog to a different area, that would be a last resort. Even if your garden isn’t necessarily hedgehog friendly that does not bother them as long as they can roam. Which is of course what you are also worried about. But hedgehogs have an area they roam across and removing them from that area, i.e. out of the city into the country, is likely to put them at very high risk and to be stressful as well.
Is there a gate the hedgehog could have got under to get into your garden, or perhaps a gate that was open which is now closed and would explain why it might be trapped? If it is trapped that certainly needs to be sorted out quickly, but hedgehogs are surprising escape artists, so it might not be as trapped as you think.
I have seen seemingly large hogs squeeze under a ground bird feeder, only about three inches or less off the ground. So getting under a gate is well within the realms of possibilities. They can also get between the bars of a bird feeder cage that can stop pigeons and cats. Again those bar are only two to three inches apart. But it does depend on the hog in question.
If it is trapped then you will need to get it out of your garden so that it can roam properly. I would perhaps call a local hedgehog rescue/carer and ask their advice. They may know the locale better and can certainly give you a better answer then I can. if you call the BHPS on 01584 890801 then they can tell you your nearest three rescues or may be able to advise you themselves.
Just a couple of other questions. How early in the morning did you see it that time? Also are you putting out water as well as the food?
One final thought. If you have a gate into the garden and the gate is wooden is it possible to cut a hedgehog hole in it?
