Hogs usually make several visits during the night, so it’s difficult to say how many. It could be just the one, if it isn’t going far, but if there are hourly visits all night, perhaps more likely that there are more than one.
Are you watching them mostly on video? If you watch them in real time at all (which I recommend as I think you see more that way – although obviously not all night!), if you look very carefully, you will see that they all have differences and it is possible to tell them apart as you would, for instance, a horse.
Things to look out for are facial colouring and marks, such as ‘stars’ (as in horses), marks under their eyes, under their ears, across their face, etc. My profile picture is actually a template which you can use to draw the facial markings. Not only does drawing them make you look more closely, but means you also have an image to compare the hogs with. Then there are other identifying features, such as the skirt (the area beneath the spines which is hairy) and the band between skirt and spines. These can vary in colour and the skirt sometimes has different gradations of colouring. The spines themselves can be darker or lighter or different shades of brown.
It can be very rewarding identifying hedgehogs in this way, getting to know individual hogs without interfering with their lives.
Whether you decide to try to identify the hogs, or not, I hope you continue to enjoy their visits.