Hi elsa60
I’m glad you’ve raised this subject again and that you have realised, independently, that they all look different. I have written many times on here trying to encourage people to identify their visiting hogs by their natural markings instead of artificially marking them. My profile pic is a sort of template to help people make sketches of their faces to help with identification in the future. The markings on their face can be very varied.
By recognising hogs in this manner I have in the past been able to recognise hogs year after year. Like you I started ‘by mistake’. I just started recognising certain hogs and then more and more of them. Making sketches and notes is really useful, as you then have a record. I used to draw a face and a side view of the whole hog, with notes, to keep as a record.
There are many different characteristics to look out for. The colour and shade of their skirts, their spines, the band between them, and the face of course. (whether they have a star – as in a horse- whether any dark comes up to the eyes, bars across the face above the nose, etc.) Sometimes even their legs and feet can be useful. Some hogs have blotches of different colours, or pale feet, etc.
The problem is that there are certain people who have begun to excessively mark hogs and this is not only bad for the hedgehog and possibly even the hedgehog population, but also sometimes covers up their natural markings. It is possible that the white marks on top of the hog, which you mention, could be artificial.
Good luck with continuing to identify them. You might find there are even more than you think when you start looking at them really closely!