How lovely that you have a hedgehog in your garden!
I’m not sure what the dog biscuits are like, but you could also try leaving a bit of wet dog or cat food or cat/kitten biscuits.
Well done offering some water. It’s best to leave some water available all day every day. You never know when a thirsty hog may turn up, even during the day, especially in the dry weather we’ve had. Wide but shallow plant saucers are ideal and the birds might welcome them during the day, too.
Try to make sure that your dog doesn’t try to pick up a hog – for the benefit of both of them. Dogs can easily leave puncture marks in hogs (even if they only held them for a very short time) which are difficult to see, but can become infected. But a dog’s mouth can also be injured by those hog prickles.
You might want to consider installing a hog house at some stage. There are various shapes and sizes. https://www.hedgehogstreet.org/help-hedgehogs/hedgehog-homes/
Also trying to make your garden more wildlife friendly is good for the hogs as well as other wildlife. I’ll put a link in the next post. (the Forum sometimes doesn’t like more than one link per post).