I was driving past a local industrial estate one day, and saw this back door to one of the industrial units, and it stood out to me as a great photo opportunity. I couldn’t photograph the door from the public road as there was a fence between me and it so I decided to walk around. However, the unit was in use, and although there were no physical restrictions to walking around the back, I thought it appropriate to ask the owners if it was OK to take a photo of their back door. After all, I didn’t want to appear suspicious. Instead I thought I would leave them thinking I was mad!