Mission accomplished, car refuelled. And I feel the need for a tiny rant...
I installed the ESSO App. It was a newer than the one I failed to use back in April, and the accompanying email assured me it would always show payment completion, and in fact I should make sure that happens before driving off - else I might not have paid. And that reassurance addressed all my concerns. So after a quick trial run at home (it correctly told me I wasn't at a garage) off I drove, quite excitedly, to a real Esso garage.
On arrival I opened the App, got a spinning 'wait' Icon, with no indication what it was waiting for, that lasted a good 2 or 3 minutes. It then located me somewhere in New Jersey. Then it complained I had to allow location access (it was already allowed) , then all of a sudden it correctly located me. Unfortunately I was at pump 7, and the only pump it would let me select was pump 1. I could have authorised payment for pump 1, but that seemed unwise. With hindsight, I could have manoeuvred the car to Pump 1, but didn't think of it at the time.
I unloaded and restarted the App for a second try. It repeated all of above steps (except new Jersey), then suddenly blanked its view, declared it was 'closed for maintenance', or something similar, 'Please try again later'. I resigned myself to paying in the shop if I wanted to buy any petrol, grateful that I had brought a mask.
For the actual refuelling aspect there were signs that I liked on every pump, mandating that
Disposable Gloves Must Be Worn,. There was also a glove dispenser on every pump, all of them empty. I carry a box of latex gloves in the car so wore my own, but nobody else had gloves on.
In the shop, there was a narrow corridor leading from the (closed, non automatic) door to the checkout desk, with 2 metre markings for the queue, generally being observed. After paying, rather than walk the long way around the shop, other customers were navigating back down the same narrow corridor towards the door, squeezing past those waiting to pay. Some were masked, others not.
I'd lost interest by now in establishing the truth about pumps being parked/resumed, sorry - none the wiser on that front.
Rant over, feeling better for it.