Hi all, thanks for your comments.
Jacqueline - you can usually find details on the British Hedgehog Preservation Society website. They're updating the site at the moment, but here is the link: http://www.hedgehogs.org.uk/www/preservationsociety/
Sarah's pondlife - nice to hear from you! happy Marion is still very active on the blogs but I;m sure you will find her on the forum, where she posts lots of lovely photos of her garden.
Lairyfairy - hedgehogs benefit from holes under fences so they can pass between gardens, leaf and log piles, compost heaps (just be careful when turning them), areas of long grass, safe access to and from your pond and no slug pellets!
Kate