There are plenty of parking options near and around Higherford Mill, there is free on street parking up and down Gisburn Road, the easiest spots are slightly up from the bridge (just outside of the Mill) on Gisburn road in the direction of Barnoldswick. Or there is the Kiln Car Park, which is about a 30 second walk from the Studio, just past the Old Bridge Pub (look for the cobbled side road entrance) shown on the map below, there is a parking charge of £1 per hour, you can pay on your return as it uses automated cameras to detect your entry and time there.