I found out that Stourhead are still running their shuttle bus. It runs between the visitor reception centre, the main entrance to the gardens, and the house. The gardens were dug out by hand and it's a steep climb back up to the car park, too steep for me still, so I hadn't been over there since before I got taken ill. Anyway, when you need a lift, you tell the person in the ticket office (or at the main reception), they call the driver on a walkie talkie, and hey presto! It's a free service too! So over I went today