I Operate from a busy garden Centre. The buisness is doing so well now we have had to start operating a booking system !
Prehaps you could try one of your local garden centres ?
Many Elderly people vist, as do young mums during the week who are unable to wash their own cars. Whilst they go for a bite to eat in the coffee shop, and do a spot of shopping I do the bizz on the cars. Once the car is ready I send a text message to their mobile phone, this saves them asking if the car is done yet, or trying to find them in the shop. You also tend to find people will leave cars on the way to work and pick them up at lunch time, or the end of the day when they finish work.
Be carefull though you would need to find a garden centre which has a good reputation, with a reasonable footfall of customers during the week. It has worked for me