Hi Judith
Welcome!
One really important thing you could do is make sure there is a plentiful supply of water available. The only slight worry is – if you see hedgehogs out during the day, there may be something wrong with them (for instance dehydration) and they may need help. I am not sure when you say they were having a nap in the shade of some bushes, how open you meant that was. I sometimes see a hog sleeping in a flower bed during the day (mine are quite thickly vegetated!), and would not worry about that, but they would not normally be in a more open place, so that might be something to look out for in the future.
Whilst improving their habitat is really the most important thing, as I see it, if you do feel you would like to give them some supplementary food then cat/dog food, cat/kitten biscuits or a reputable hedgehog food are currently thought to be best. Whilst they would welcome food at times of need, especially in very dry weather, before and after hibernation, etc. supplementary, is the operative word. They really need to be able to find some wild food for themselves as well, then the less than ideal nature of what we supplementary feed them, becomes less important in terms of content. I tend to only feed for 2 or 3 hours each night (when I am up to watch them) so I can keep an eye on them (from a respectful distance, unless there looks to be a problem). Sounds like you are well on your way to making your garden a good supply of natural food, but one garden is never enough (unless it is enormous, of course) so linking gardens is important.
Good luck – I hope you see the hedgehogs again – and, perhaps, some of their relatives.
