Good point about doing the work when the petrol station is closed....but if they're anything like the one's we deal with ...they either open 24/7 or open at 6am and close at 10pm.
I had to clean a forecourt car wash, which for me is a bit like 'the Turkey voting for Christmas'
(we do car valeting) and all I got was people driving all over my hoses and power cables + wingeing because they wanted to wash their car.
When we clean and treat the forecourt shop floors it has to be done between 8 - 10 pm. I had to get the garages to sign a disclaimer to prevent a claim against us if anyone falls 'whatsit over thingy'.