Hi MarkUK
Yes, you do need to go to ‘Home’ to get to the Big Hedgehog Map (unless you have the link directly there). The information in ‘My Hedgehog Street’ is only for registered Hedgehog Champions. I believe, theoretically, anyone who has data about the presence of hogs can enter it onto the Big Hedgehog Map. Also it is possible to enter hedgehog sightings from places other than your home address, so that linking it with the information from My Hedgehog Street, would not necessarily be helpful.
Well done for finding the map, though. I hope you managed to log all the hogs ok.