That is so sad. I don’t know why they wouldn’t let you have one of the ones you rescued back – they usually do. And I’m sorry to hear about the dead hedgehog. I can see why you are disappointed, especially when there is a lovely des res waiting for them.
The only consolation is that if there was one (and last year obviously two!) adult hedgehog(s) around it is quite likely that there will be other ones. I would look out for hedgehog poos in your garden. (if they have been eating proper wild food, they are normally very dark, almost black, often with shiny beetle wings visible). I don’t know how wildlife friendly your garden is, but most of us can improve things from a hog viewpoint. I know I can. So I would try to improve the hog friendliness, so that they think it is a really nice place to visit anyway, regardless of artificial food. (I am presuming they have easy access). If/when you see signs of hogs, you could try putting out a bit of food (cat/dog/hog food) if you would like to. The trouble is, if there are no signs of hogs in the garden, it may well attract unwanted visitors, so I think habitat improvements would be a good way to start. I always think it is best to let the hogs find you.
It may well be that when the hoglets are around again, they may find your garden. Good luck. I hope you have some visitors soon.
P.S. Love your profile pic – very clever!