Hi Prof and Sammy9
There are all sorts of hazards out there for hedgehogs, so you can never be sure, but it is quite normal for hedgehogs not to visit every night. The males tend to have bigger ranges than the females, so may be visiting another part of their range. Or they may be off somewhere courting other females. There are males which I was seeing fairly regularly earlier in the year who I often don’t see for days, or weeks at a time. Then they might suddenly turn up again. The females, if they have hoglets, often disappear for a while – sometimes as much as a couple of weeks.
They will know you are there so, all being well, will likely return when they are ready. I know it is always a bit of a worry, but there isn’t really anything much you can do other than what you probably are doing – providing food and water, creating a good habitat for them, etc. The better you can make the habitat in your garden, the more likely you will get more hogs visiting.
I hope they return soon – you never know, maybe with hoglets?