Hedgehogs and British Banknotes

I have two allotments, one a large orchard and the other one is for our vegetables. Each year we clear the weeds, dig over, cut away the invading brambles from the allotments on either side and have a fire to burn the garden rubbish that cannot be composted. We are advised to keep an eye out for sleeping hedgehogs so before igniting any fire we check underneath for our prickly friends. Perhaps it’s time to look into the collection and see if there is anything that needs to be cleared out, replaced or is there a gap to be filled?