A dry space underneath garden shed make good hibernaculum with a bundle of dry straw or hay. Don't be so tidy with the garden. Leave corners and bases of hedges unkempt. Don't send your cut wood to the tip, burn it or shred it. Instead, make logpiles that will attract not just hedgehogs but many hibernating insects, frogs and toads.
Dead wood can be the life of a garden.
Be aware if cutting back rank vegetation over the winter that you may be destroying a hedgehog hibernaculum . They are not as obvious as you may think and catching them with a grass hook or a strimmer can be fatal. Ponds and cattle grids are potential death traps. Ensure your pond has at least one gently sloping bank or rocks can be used to climb out should they fall in. Hedgehogs can be active occasionally over the winter.